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diff --git a/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml b/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml deleted file mode 100644 index cfd6981758a..00000000000 --- a/docs-xml/Samba3-ByExample/SBE-2000UserNetwork.xml +++ /dev/null @@ -1,1590 +0,0 @@ -<?xml version="1.0" encoding="iso-8859-1"?> -<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc"> -<chapter id="net2000users"> - <title>A Distributed 2000-User Network</title> - -<para> -There is something indeed mystical about things that are -big. Large networks exhibit a certain magnetism and exude a sense of -importance that obscures reality. You and I know that it is no more -difficult to secure a large network than it is a small one. We all -know that over and above a particular number of network clients, the -rules no longer change; the only real dynamic is the size of the domain -(much like a kingdom) over which the network ruler (oops, administrator) -has control. The real dynamic then transforms from the technical to the -political. Then again, that point is often reached well before the -kingdom (or queendom) grows large. -</para> - -<para> -If you have systematically worked your way to this chapter, hopefully you -have found some gems and techniques that are applicable in your -world. The network designs you have worked with in this book have their -strong points as well as weak ones. That is to be expected given that -they are based on real business environments, the specifics of which are -molded to serve the purposes of this book. -</para> - -<para> -This chapter is intent on wrapping up issues that are central to -implementation and design of progressively larger networks. Are you ready -for this chapter? Good, it is time to move on. -</para> - -<para> -In previous chapters, you made the assumption that your network -administration staff need detailed instruction right down to the -nuts and bolts of implementing the solution. That is still the case, -but they have graduated now. You decide to document only those issues, -methods, and techniques that are new or complex. Routine tasks such as -implementing a DNS or a DHCP server are under control. Even the basics of -Samba are largely under control. So in this section you focus on the -specifics of implementing LDAP changes, Samba changes, and approach and -design of the solution and its deployment. -</para> - -<sect1> -<title>Introduction</title> - -<para> -Abmas is a miracle company. Most businesses would have collapsed under -the weight of rapid expansion that this company has experienced. Samba -is flexible, so there is no need to reinstall the whole operating -system just because you need to implement a new network design. In fact, -you can keep an old server running right up to the moment of cutover -and then do a near-live conversion. There is no need to reinstall a -Samba server just to change the way your network should function. -</para> - -<para> -<indexterm><primary>LDAP</primary></indexterm> -Network growth is common to all organizations. In this exercise, -your preoccupation is with the mechanics of implementing Samba and -LDAP so that network users on each network segment can work -without impediment. -</para> - - <sect2> - <title>Assignment Tasks</title> - - <para> - Starting with the configuration files for the server called - <constant>MASSIVE</constant> in <link linkend="happy"/>, you now deal with the - issues that are particular to large distributed networks. Your task - is simple &smbmdash; identify the challenges, consider the - alternatives, and then design and implement a solution. - </para> - - <para> - <indexterm><primary>VPN</primary></indexterm> - Remember, you have users based in London (UK), Los Angeles, - Washington. DC, and, three buildings in New York. A significant portion - of your workforce have notebook computers and roam all over the - world. Some dial into the office, others use VPN connections over the - Internet, and others just move between buildings.i - </para> - - <para> - What do you say to an employee who normally uses a desktop - system but must spend six weeks on the road with a notebook computer? - She is concerned about email access and how to keep coworkers current - with changing documents. - </para> - - <para> - To top it all off, you have one network support person and one - help desk person based in London, a single person dedicated to all - network operations in Los Angeles, five staff for user administration - and help desk in New York, plus one <emphasis>floater</emphasis> for - Washington. - </para> - - <para> - You have outsourced all desktop deployment and management to - DirectPointe. Your concern is server maintenance and third-level - support. Build a plan and show what must be done. - </para> - - </sect2> -</sect1> - -<sect1> -<title>Dissection and Discussion</title> - -<para> -<indexterm><primary>passdb backend</primary></indexterm> -<indexterm><primary>LDAP</primary></indexterm> -In <link linkend="happy"/>, you implemented an LDAP server that provided the -<parameter>passdb backend</parameter> for the Samba servers. You -explored ways to accelerate Windows desktop profile handling and you -took control of network performance. -</para> - -<para> -<indexterm><primary>ldapsam</primary></indexterm> -<indexterm><primary>tdbsam</primary></indexterm> -<indexterm><primary>smbpasswd</primary></indexterm> -<indexterm><primary>replicated</primary></indexterm> -The implementation of an LDAP-based passdb backend (known as -<emphasis>ldapsam</emphasis> in Samba parlance), or some form of database -that can be distributed, is essential to permit the deployment of Samba -Primary and Backup Domain Controllers (PDC/BDCs). You see, the problem -is that the <emphasis>tdbsam</emphasis>-style passdb backend does not -lend itself to being replicated. The older plain-text-based -<emphasis>smbpasswd</emphasis>-style passdb backend can be replicated -using a tool such as <command>rsync</command>, but -<emphasis>smbpasswd</emphasis> suffers the drawback that it does not -support the range of account facilities demanded by modern network -managers. -</para> - -<para> -<indexterm><primary>XML</primary></indexterm> -<indexterm><primary>SQL</primary></indexterm> -The new <emphasis>tdbsam</emphasis> facility supports functionality -that is similar to an <emphasis>ldapsam</emphasis>, but the lack of -distributed infrastructure sorely limits the scope for its -deployment. This raises the following questions: Why can't I just use -an XML-based backend, or for that matter, why not use an SQL-based -backend? Is support for these tools broken? Answers to these -questions require a bit of background.</para> - -<para> -<indexterm><primary>directory</primary></indexterm> -<indexterm><primary>database</primary></indexterm> -<indexterm><primary>transaction processing</primary></indexterm> -<indexterm><primary>LDAP</primary></indexterm> -<emphasis>What is a directory?</emphasis> A directory is a -collection of information regarding objects that can be accessed to -rapidly find information that is relevant in a particular and -consistent manner. A directory differs from a database in that it is -generally more often searched (read) than updated. As a consequence, the -information is organized to facilitate read access rather than to -support transaction processing.</para> - -<para> -<indexterm><primary>Lightweight Directory Access Protocol</primary><see>LDAP</see></indexterm> -<indexterm><primary>LDAP</primary></indexterm> -<indexterm><primary>master</primary></indexterm> -<indexterm><primary>slave</primary></indexterm> -The Lightweight Directory Access Protocol (LDAP) differs -considerably from a traditional database. It has a simple search -facility that uniquely makes a highly preferred mechanism for managing -user identities. LDAP provides a scalable mechanism for distributing -the data repository and for keeping all copies (slaves) in sync with -the master repository.</para> - -<para> -<indexterm><primary>identity management</primary></indexterm> -<indexterm><primary>Active Directory</primary></indexterm> -<indexterm><primary>OpenLDAP</primary></indexterm> -Samba is a flexible and powerful file and print sharing -technology. It can use many external authentication sources and can be -part of a total authentication and identity management -infrastructure. The two most important external sources for large sites -are Microsoft Active Directory and LDAP. Sites that specifically wish to -avoid the proprietary implications of Microsoft Active Directory -naturally gravitate toward OpenLDAP.</para> - -<para> -<indexterm><primary>network</primary><secondary>routed</secondary></indexterm> -In <link linkend="happy"/>, you had to deal with a locally routed -network. All deployment concerns focused around making users happy, -and that simply means taking control over all network practices and -usage so that no one user is disadvantaged by any other. The real -lesson is one of understanding that no matter how much network -bandwidth you provide, bandwidth remains a precious resource.</para> - -<para>In this chapter, you must now consider how the overall network must -function. In particular, you must be concerned with users who move -between offices. You must take into account the way users need to -access information globally. And you must make the network robust -enough so that it can sustain partial breakdown without causing loss of -productivity.</para> - - <sect2> - <title>Technical Issues</title> - - <para> - There are at least three areas that need to be addressed as you - approach the challenge of designing a network solution for the newly - expanded business: - </para> - - <itemizedlist> - <listitem><para><indexterm><primary>mobility</primary></indexterm> - User needs such as mobility and data access</para></listitem> - - <listitem><para>The nature of Windows networking protocols</para></listitem> - - <listitem><para>Identity management infrastructure needs</para></listitem> - </itemizedlist> - - <para>Let's look at each in turn.</para> - - <sect3> - <title>User Needs</title> - - <para> - The new company has three divisions. Staff for each division are spread across - the company. Some staff are office-bound and some are mobile users. Mobile - users travel globally. Some spend considerable periods working in other offices. - Everyone wants to be able to work without constraint of productivity. - </para> - - <para> - The challenge is not insignificant. In some parts of the world, even dial-up - connectivity is poor, while in other regions political encumbrances severely - curtail user needs. Parts of the global Internet infrastructure remain shielded - off for reasons outside the scope of this discussion. - </para> - - <para> - <indexterm><primary>synchronize</primary></indexterm> - Decisions must be made regarding where data is to be stored, how it will be - replicated (if at all), and what the network bandwidth implications are. For - example, one decision that can be made is to give each office its own master - file storage area that can be synchronized to a central repository in New - York. This would permit global data to be backed up from a single location. - The synchronization tool could be <command>rsync,</command> run via a cron - job. Mobile users may use off-line file storage under Windows XP Professional. - This way, they can synchronize all files that have changed since each logon - to the network. - </para> - - <para> - <indexterm><primary>bandwidth</primary><secondary>requirements</secondary></indexterm> - <indexterm><primary>roaming profile</primary></indexterm> - No matter which way you look at this, the bandwidth requirements - for acceptable performance are substantial even if only 10 percent of - staff are global data users. A company with 3,500 employees, - 280 of whom are mobile users who use a similarly distributed - network, found they needed at least 2 Mb/sec connectivity - between the UK and US offices. Even over 2 Mb/sec bandwidth, this - company abandoned any attempt to run roaming profile usage for - mobile users. At that time, the average roaming profile took 480 - KB, while today the minimum Windows XP Professional roaming - profile involves a transfer of over 750 KB from the profile - server to and from the client. - </para> - - <para> - <indexterm><primary>wide-area</primary></indexterm> - Obviously then, user needs and wide-area practicalities dictate the economic and - technical aspects of your network design as well as for standard operating procedures. - </para> - - </sect3> - - <sect3> - <title>The Nature of Windows Networking Protocols</title> - - <para> - <indexterm><primary>profile</primary><secondary>mandatory</secondary></indexterm> - Network logons that include roaming profile handling requires from 140 KB to 2 MB. - The inclusion of support for a minimal set of common desktop applications can push - the size of a complete profile to over 15 MB. This has substantial implications - for location of user profiles. Additionally, it is a significant factor in - determining the nature and style of mandatory profiles that may be enforced as - part of a total service-level assurance program that might be implemented. - </para> - - <para> - <indexterm><primary>logon traffic</primary></indexterm> - <indexterm><primary>redirected folders</primary></indexterm> - One way to reduce the network bandwidth impact of user logon - traffic is through folder redirection. In <link linkend="happy"/>, you - implemented this in the new Windows XP Professional standard - desktop configuration. When desktop folders such as <guimenu>My - Documents</guimenu> are redirected to a network drive, they should - also be excluded from synchronization to and from the server on - logon or logout. Redirected folders are analogous to network drive - connections. - </para> - - <para><indexterm><primary>application servers</primary></indexterm> - Of course, network applications should only be run off - local application servers. As a general rule, even with 2 Mb/sec - network bandwidth, it would not make sense at all for someone who - is working out of the London office to run applications off a - server that is located in New York. - </para> - - <para> - <indexterm><primary>affordability</primary></indexterm> - When network bandwidth becomes a precious commodity (that is most - of the time), there is a significant demand to understand network - processes and to mold the limits of acceptability around the - constraints of affordability. - </para> - - <para> - When a Windows NT4/200x/XP Professional client user logs onto - the network, several important things must happen. - </para> - - <itemizedlist> - <listitem><para> - <indexterm><primary>DHCP</primary></indexterm> - The client obtains an IP address via DHCP. (DHCP is - necessary so that users can roam between offices.) - </para></listitem> - - <listitem><para> - <indexterm><primary>WINS</primary></indexterm> - <indexterm><primary>DNS</primary></indexterm> - The client must register itself with the WINS and/or DNS server. - </para></listitem> - - <listitem><para> - <indexterm><primary>Domain Controller</primary><secondary>closest</secondary></indexterm> - The client must locate the closest domain controller. - </para></listitem> - - <listitem><para> - The client must log onto a domain controller and obtain as part of - that process the location of the user's profile, load it, connect to - redirected folders, and establish all network drive and printer connections. - </para></listitem> - - <listitem><para> - The domain controller must be able to resolve the user's - credentials before the logon process is fully implemented. - </para></listitem> - </itemizedlist> - - <para> - Given that this book is about Samba and that it implements the Windows - NT4-style domain semantics, it makes little sense to compare Samba with - Microsoft Active Directory insofar as the logon protocols and principles - of operation are concerned. The following information pertains exclusively - to the interaction between a Windows XP Professional workstation and a - Samba-3.0.20 server. In the discussion that follows, use is made of DHCP and WINS. - </para> - - <para> - As soon as the Windows workstation starts up, it obtains an - IP address. This is immediately followed by registration of its - name both by broadcast and Unicast registration that is directed - at the WINS server. - </para> - - <para> - <indexterm><primary>Unicast</primary></indexterm> - <indexterm><primary>broadcast</primary><secondary>directed</secondary> - </indexterm><indexterm><primary>NetBIOS</primary></indexterm> - Given that the client is already a domain member, it then sends - a directed (Unicast) request to the WINS server seeking the list of - IP addresses for domain controllers (NetBIOS name type 0x1C). The - WINS server replies with the information requested.</para> - - <para> - <indexterm><primary>broadcast</primary><secondary>mailslot</secondary></indexterm> - <indexterm><primary>Unicast</primary></indexterm> - <indexterm><primary>WINS</primary></indexterm> - The client sends two netlogon mailslot broadcast requests - to the local network and to each of the IP addresses returned by - the WINS server. Whichever answers this request first appears to - be the machine that the Windows XP client attempts to use to - process the network logon. The mailslot messages use UDP broadcast - to the local network and UDP Unicast directed at each machine that - was listed in the WINS server response to a request for the list of - domain controllers. - </para> - - <para> - <indexterm><primary>protocol</primary><secondary>negotiation</secondary></indexterm> - <indexterm><primary>logon server</primary></indexterm> - <indexterm><primary>fail</primary></indexterm> - The logon process begins with negotiation of the SMB/CIFS - protocols that are to be used; this is followed by an exchange of - information that ultimately includes the client sending the - credentials with which the user is attempting to logon. The logon - server must now approve the further establishment of the - connection, but that is a good point to halt for now. The priority - here must center around identification of network infrastructure - needs. A secondary fact we need to know is, what happens when - local domain controllers fail or break? - </para> - - <para> - <indexterm><primary>Domain Controller</primary></indexterm> - <indexterm><primary>PDC</primary></indexterm> - <indexterm><primary>BDC</primary></indexterm> - <indexterm><primary>netlogon</primary></indexterm> - Under most circumstances, the nearest domain controller - responds to the netlogon mailslot broadcast. The exception to this - norm occurs when the nearest domain controller is too busy or is out - of service. Herein lies an important fact. This means it is - important that every network segment should have at least two - domain controllers. Since there can be only one PDC, all additional - domain controllers are by definition BDCs. - </para> - - <para> - <indexterm><primary>authentication</primary></indexterm> - <indexterm><primary>Identity Management</primary></indexterm> - The provision of sufficient servers that are BDCs is an - important design factor. The second important design factor - involves how each of the BDCs obtains user authentication - data. That is the subject of the next section, which involves key - decisions regarding Identity Management facilities. - </para> - - </sect3> - - <sect3> - <title>Identity Management Needs</title> - - <para> - <indexterm><primary>privacy</primary></indexterm> - <indexterm><primary>user credentials</primary></indexterm> - <indexterm><primary>validated</primary></indexterm> - <indexterm><primary>privileges</primary></indexterm> - Network managers recognize that in large organizations users - generally need to be given resource access based on needs, while - being excluded from other resources for reasons of privacy. It is - therefore essential that all users identify themselves at the - point of network access. The network logon is the principal means - by which user credentials are validated and filtered and appropriate - rights and privileges are allocated. - </para> - - <para> - <indexterm><primary>Identity Management</primary></indexterm> - <indexterm><primary>Yellow Pages</primary></indexterm> - <indexterm><primary>NIS</primary></indexterm> - Unfortunately, network resources tend to have their own Identity - Management facilities, the quality and manageability of which varies - from quite poor to exceptionally good. Corporations that use a mixture - of systems soon discover that until recently, few systems were - designed to interoperate. For example, UNIX systems each have an - independent user database. Sun Microsystems developed a facility that - was originally called <constant>Yellow Pages</constant>, and was renamed - when a telephone company objected to the use of its trademark. - What was once called <constant>Yellow Pages</constant> is today known - as <constant>Network Information System</constant> (NIS). - </para> - - <para> - <indexterm><primary>NIS+</primary></indexterm> - NIS gained a strong following throughout the UNIX/VMS space in a short - period of time and retained that appeal and use for over a decade. - Security concerns and inherent limitations have caused it to enter its - twilight. NIS did not gain widespread appeal outside of the UNIX world - and was not universally adopted. Sun updated this to a more secure - implementation called NIS+, but even it has fallen victim to changing - demands as the demand for directory services that can be coupled with - other information systems is catching on. - </para> - - - <para> - <indexterm><primary>NIS</primary></indexterm> - <indexterm><primary>government</primary></indexterm> - <indexterm><primary>education</primary></indexterm> - Nevertheless, both NIS and NIS+ continue to hold ground in - business areas where UNIX still has major sway. Examples of - organizations that remain firmly attached to the use of NIS and - NIS+ include large government departments, education institutions, - and large corporations that have a scientific or engineering - focus. - </para> - - <para> - <indexterm><primary>scalable</primary></indexterm> - <indexterm><primary>distributed</primary></indexterm> - Today's networking world needs a scalable, distributed Identity - Management infrastructure, commonly called a directory. The most - popular technologies today are Microsoft Active Directory service - and a number of LDAP implementations. - </para> - - <para> - <indexterm><primary>multiple directories</primary></indexterm> - The problem of managing multiple directories has become a focal - point over the past decade, creating a large market for - metadirectory products and services that allow organizations that - have multiple directories and multiple management and control - centers to provision information from one directory into - another. The attendant benefit to end users is the promise of - having to remember and deal with fewer login identities and - passwords.</para> - - <para> - <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> - The challenge of every large network is to find the optimum - balance of internal systems and facilities for Identity - Management resources. How well the solution is chosen and - implemented has potentially significant impact on network bandwidth - and systems response needs.</para> - - <para> - <indexterm><primary>LDAP server</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>master</secondary></indexterm> - <indexterm><primary>LDAP</primary><secondary>slave</secondary></indexterm> - In <link linkend="happy"/>, you implemented a single LDAP server for the - entire network. This may work for smaller networks, but almost - certainly fails to meet the needs of large and complex networks. The - following section documents how you may implement a single - master LDAP server with multiple slave servers.</para> - - <para> - What is the best method for implementing master/slave LDAP - servers within the context of a distributed 2,000-user network is a - question that remains to be answered.</para> - - <para> - <indexterm><primary>distributed domain</primary></indexterm> - <indexterm><primary>wide-area</primary></indexterm> - One possibility that has great appeal is to create a single, - large distributed domain. The practical implications of this - design (see <link linkend="chap7net"/>) demands the placement of - sufficient BDCs in each location. Additionally, network - administrators must make sure that profiles are not transferred - over the wide-area links, except as a totally unavoidable - measure. Network design must balance the risk of loss of user - productivity against the cost of network management and - maintenance. - </para> - - <para> - <indexterm><primary>domain name space</primary></indexterm> - The network design in <link linkend="chap7net2"/> takes the approach - that management of networks that are too remote to be managed - effectively from New York ought to be given a certain degree of - autonomy. With this rationale, the Los Angeles and London networks, - though fully integrated with those on the East Coast, each have their - own domain name space and can be independently managed and controlled. - One of the key drawbacks of this design is that it flies in the face of - the ability for network users to roam globally without some compromise - in how they may access global resources. - </para> - - <para> - <indexterm><primary>interdomain trusts</primary></indexterm> - Desk-bound users need not be negatively affected by this design, since - the use of interdomain trusts can be used to satisfy the need for global - data sharing. - </para> - - <para> - <indexterm><primary>LDAP</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>backend</secondary></indexterm> - <indexterm><primary>SID</primary></indexterm> - When Samba is configured to use an LDAP backend, it stores the domain - account information in a directory entry. This account entry contains the - domain SID. An unintended but exploitable side effect is that this makes it - possible to operate with more than one PDC on a distributed network. - </para> - - <para> - <indexterm><primary>WINS</primary></indexterm> - <indexterm><primary>wins.dat</primary></indexterm> - <indexterm><primary>SID</primary></indexterm> - How might this peculiar feature be exploited? The answer is simple. It is - imperative that each network segment have its own WINS server. Major - servers on remote network segments can be given a static WINS entry in - the <filename>wins.dat</filename> file on each WINS server. This allows - all essential data to be visible from all locations. Each location would, - however, function as if it is an independent domain, while all sharing the - same domain SID. Since all domain account information can be stored in a - single LDAP backend, users have unfettered ability to roam. - </para> - - <para> - <indexterm><primary>NetBIOS name</primary><secondary>aliases</secondary></indexterm> - <indexterm><primary>fail-over</primary></indexterm> - This concept has not been exhaustively validated, though we can see no reason - why this should not work. The important facets are the following: The name of - the domain must be identical in all locations. Each network segment must have - its own WINS server. The name of the PDC must be the same in all locations; this - necessitates the use of NetBIOS name aliases for each PDC so that they can be - accessed globally using the alias and not the PDC's primary name. A single master - LDAP server can be based in New York, with multiple LDAP slave servers located - on every network segment. Finally, the BDCs should each use failover LDAP servers - that are in fact slave LDAP servers on the local segments. - </para> - - <para> - <indexterm><primary>LDAP</primary><secondary>updates</secondary></indexterm> - <indexterm><primary>domain tree</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>database</secondary></indexterm> - <indexterm><primary>LDAP</primary><secondary>directory</secondary></indexterm> - With a single master LDAP server, all network updates are effected on a single - server. In the event that this should become excessively fragile or network - bandwidth limiting, one could implement a delegated LDAP domain. This is also - known as a partitioned (or multiple partition) LDAP database and as a distributed - LDAP directory. - </para> - - <para> - As the LDAP directory grows, it becomes increasingly important - that its structure is implemented in a manner that mirrors - organizational needs, so as to limit network update and - referential traffic. It should be noted that all directory - administrators must of necessity follow the same standard - procedures for managing the directory, because retroactive correction of - inconsistent directory information can be exceedingly difficult. - </para> - - </sect3> - - </sect2> - - - <sect2> - <title>Political Issues</title> - - <para> - As organizations grow, the number of points of control increases - also. In a large distributed organization, it is important that the - Identity Management system be capable of being updated from - many locations, and it is equally important that changes made should - become usable in a reasonable period, typically - minutes rather than days (the old limitation of highly manual - systems). - </para> - - </sect2> - -</sect1> - -<sect1> - <title>Implementation</title> - - <para> - <indexterm><primary>winbind</primary></indexterm> - <indexterm><primary>LDAP</primary></indexterm> - <indexterm><primary>UID</primary></indexterm> - <indexterm><primary>GID</primary></indexterm> - Samba has the ability to use multiple password (authentication and - identity resolution) backends. The diagram in <link linkend="chap7idres"/> - demonstrates how Samba uses winbind, LDAP, and NIS, the traditional system - password database. The diagram only documents the mechanisms for - authentication and identity resolution (obtaining a UNIX UID/GID) - using the specific systems shown. - </para> - - <figure id="chap7idres"> - <title>Samba and Authentication Backend Search Pathways</title> - <imagefile scale="55">chap7-idresol</imagefile> - </figure> - - <para> - <indexterm><primary>smbpasswd</primary></indexterm> - <indexterm><primary>xmlsam</primary></indexterm> - <indexterm><primary>SMB passwords</primary></indexterm> - <indexterm><primary>tdbsam</primary></indexterm> - <indexterm><primary>mysqlsam</primary></indexterm> - <indexterm><primary>LDAP</primary></indexterm> - <indexterm><primary>distributed</primary></indexterm> - Samba is capable of using the <constant>smbpasswd</constant> and - <constant>tdbsam</constant>. The SMB - passwords can, of course, also be stored in an LDAP ldapsam - backend. LDAP is the preferred passdb backend for distributed network - operations. - </para> - - <para> - <indexterm><primary>passdb backend</primary></indexterm> - You can specify a failover LDAP backend. The syntax for specifying a - single LDAP backend in &smb.conf; is: -<screen> -... -passdb backend = ldapsam:ldap://master.abmas.biz -... -</screen> - This configuration tells Samba to use a single LDAP server, as shown in <link linkend="ch7singleLDAP"/>. - <figure id="ch7singleLDAP"> - <title>Samba Configuration to Use a Single LDAP Server</title> - <imagefile scale="65">ch7-singleLDAP</imagefile> - </figure> - <indexterm><primary>LDAP</primary><secondary>fail-over</secondary></indexterm> - <indexterm><primary>fail-over</primary></indexterm> - The addition of a failover LDAP server can simply be done by adding a - second entry for the failover server to the single <parameter>ldapsam</parameter> - entry, as shown here (note the particular use of the double quotes): -<screen> -... -passdb backend = ldapsam:"ldap://master.abmas.biz \ - ldap://slave.abmas.biz" -... -</screen> - This configuration tells Samba to use a master LDAP server, with failover to a slave server if necessary, - as shown in <link linkend="ch7dualLDAP"/>. - <figure id="ch7dualLDAP"> - <title>Samba Configuration to Use a Dual (Fail-over) LDAP Server</title> - <imagefile scale="65">ch7-fail-overLDAP</imagefile> - </figure> - </para> - - <para> - It is assumed that the network you are working with follows in a - pattern similar to what was covered in <link linkend="happy"/>. The following steps - permit the operation of a master/slave OpenLDAP arrangement. - </para> - - <procedure> - <title>Implementation Steps for an LDAP Slave Server</title> - - <step><para> - <indexterm><primary>SUSE Linux</primary></indexterm> - <indexterm><primary>Red Hat Linux</primary></indexterm> - Log onto the master LDAP server as <constant>root</constant>. - You are about to change the configuration of the LDAP server, so it - makes sense to temporarily halt it. Stop OpenLDAP from running on - SUSE Linux by executing: -<screen> -&rootprompt; rcldap stop -</screen> - On Red Hat Linux, you can do this by executing: -<screen> -&rootprompt; service ldap stop -</screen> - </para></step> - - <step><para> - <indexterm><primary>/etc/openldap/slapd.conf</primary></indexterm> - Edit the <filename>/etc/openldap/slapd.conf</filename> file so it - matches the content of <link linkend="ch7-LDAP-master"/>. - </para></step> - - <step><para> - Create a file called <filename>admin-accts.ldif</filename> with the following contents: -<screen> -dn: cn=updateuser,dc=abmas,dc=biz -objectClass: person -cn: updateuser -sn: updateuser -userPassword: not24get - -dn: cn=sambaadmin,dc=abmas,dc=biz -objectClass: person -cn: sambaadmin -sn: sambaadmin -userPassword: buttercup -</screen> - </para></step> - - <step><para> - Add an account called <quote>updateuser</quote> to the master LDAP server as shown here: -<screen> -&rootprompt; slapadd -v -l admin-accts.ldif -</screen> - </para></step> - - <step><para> - <indexterm><primary>LDIF</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>preload</secondary></indexterm> - Change directory to a suitable place to dump the contents of the - LDAP server. The dump file (and LDIF file) is used to preload - the slave LDAP server database. You can dump the database by executing: -<screen> -&rootprompt; slapcat -v -l LDAP-transfer-LDIF.txt -</screen> - Each record is written to the file. - </para></step> - - <step><para> - <indexterm><primary>LDAP-transfer-LDIF.txt</primary></indexterm> - Copy the file <filename>LDAP-transfer-LDIF.txt</filename> to the intended - slave LDAP server. A good location could be in the directory - <filename>/etc/openldap/preload</filename>. - </para></step> - - <step><para> - Log onto the slave LDAP server as <constant>root</constant>. You can - now configure this server so the <filename>/etc/openldap/slapd.conf</filename> - file matches the content of <link linkend="ch7-LDAP-slave"/>. - </para></step> - - <step><para> - Change directory to the location in which you stored the - <filename>LDAP-transfer-LDIF.txt</filename> file (<filename>/etc/openldap/preload</filename>). - While in this directory, execute: -<screen> -&rootprompt; slapadd -v -l LDAP-transfer-LDIF.txt -</screen> - If all goes well, the following output confirms that the data is being loaded - as intended: -<screen> -added: "dc=abmas,dc=biz" (00000001) -added: "cn=sambaadmin,dc=abmas,dc=biz" (00000002) -added: "cn=updateuser,dc=abmas,dc=biz" (00000003) -added: "ou=People,dc=abmas,dc=biz" (00000004) -added: "ou=Groups,dc=abmas,dc=biz" (00000005) -added: "ou=Computers,dc=abmas,dc=biz" (00000006) -added: "uid=Administrator,ou=People,dc=abmas,dc=biz" (00000007) -added: "uid=nobody,ou=People,dc=abmas,dc=biz" (00000008) -added: "cn=Domain Admins,ou=Groups,dc=abmas,dc=biz" (00000009) -added: "cn=Domain Users,ou=Groups,dc=abmas,dc=biz" (0000000a) -added: "cn=Domain Guests,ou=Groups,dc=abmas,dc=biz" (0000000b) -added: "uid=bobj,ou=People,dc=abmas,dc=biz" (0000000c) -added: "sambaDomainName=MEGANET2,dc=abmas,dc=biz" (0000000d) -added: "uid=stans,ou=People,dc=abmas,dc=biz" (0000000e) -added: "uid=chrisr,ou=People,dc=abmas,dc=biz" (0000000f) -added: "uid=maryv,ou=People,dc=abmas,dc=biz" (00000010) -added: "cn=Accounts,ou=Groups,dc=abmas,dc=biz" (00000011) -added: "cn=Finances,ou=Groups,dc=abmas,dc=biz" (00000012) -added: "cn=PIOps,ou=Groups,dc=abmas,dc=biz" (00000013) -</screen> - </para></step> - - <step><para> - Now start the LDAP server and set it to run automatically on system reboot by executing: -<screen> -&rootprompt; rcldap start -&rootprompt; chkconfig ldap on -</screen> - On Red Hat Linux, execute the following: -<screen> -&rootprompt; service ldap start -&rootprompt; chkconfig ldap on -</screen> - </para></step> - - <step><para> - <indexterm><primary>chkconfig</primary></indexterm> - <indexterm><primary>service</primary></indexterm> - <indexterm><primary>rcldap</primary></indexterm> - Go back to the master LDAP server. Execute the following to start LDAP as well - as <command>slurpd</command>, the synchronization daemon, as shown here: -<screen> -&rootprompt; rcldap start -&rootprompt; chkconfig ldap on -&rootprompt; rcslurpd start -&rootprompt; chkconfig slurpd on -</screen> - <indexterm><primary>slurpd</primary></indexterm> - On Red Hat Linux, check the equivalent command to start <command>slurpd</command>. - </para></step> - - <step><para> - <indexterm><primary>smbldap-useradd</primary></indexterm> - On the master LDAP server you may now add an account to validate that replication - is working. Assuming the configuration shown in <link linkend="happy"/>, execute: -<screen> -&rootprompt; /var/lib/samba/sbin/smbldap-useradd -a fruitloop -</screen> - </para></step> - - <step><para> - On the slave LDAP server, change to the directory <filename>/var/lib/ldap</filename>. - There should now be a file called <filename>replogfile</filename>. If replication worked - as expected, the content of this file should be: -<screen> -time: 1072486403 -dn: uid=fruitloop,ou=People,dc=abmas,dc=biz -changetype: modify -replace: sambaProfilePath -sambaProfilePath: \\MASSIVE\profiles\fruitloop -- -replace: sambaHomePath -sambaHomePath: \\MASSIVE\homes -- -replace: entryCSN -entryCSN: 2003122700:43:38Z#0x0005#0#0000 -- -replace: modifiersName -modifiersName: cn=Manager,dc=abmas,dc=biz -- -replace: modifyTimestamp -modifyTimestamp: 20031227004338Z -- -</screen> - </para></step> - - <step><para> - Given that this first slave LDAP server is now working correctly, you may now - implement additional slave LDAP servers as required. - </para></step> - - <step><para> - On each machine (PDC and BDCs) after the respective &smb.conf; files have been created as shown in - <link linkend="ch7-massmbconfA">Primary Domain Controller &smb.conf; File &smbmdash; Part A + B + C</link> and - on BDCs the <link linkend="ch7-slvsmbocnfA">Backup Domain Controller &smb.conf; File &smbmdash; Part A - + B + C</link> execute the following: -<screen> -&rootprompt; smbpasswd -w buttercup -</screen> - This will install in the <filename>secrets.tdb</filename> file the password that Samba will need to - manage (write to) the LDAP Master server to perform account updates. - </para></step> - - </procedure> - -<example id="ch7-LDAP-master"> -<title>LDAP Master Server Configuration File &smbmdash; <filename>/etc/openldap/slapd.conf</filename></title> -<screen> -include /etc/openldap/schema/core.schema -include /etc/openldap/schema/cosine.schema -include /etc/openldap/schema/inetorgperson.schema -include /etc/openldap/schema/nis.schema -include /etc/openldap/schema/samba.schema - -pidfile /var/run/slapd/slapd.pid -argsfile /var/run/slapd/slapd.args - -database bdb -suffix "dc=abmas,dc=biz" -rootdn "cn=Manager,dc=abmas,dc=biz" - -# rootpw = not24get -rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV - -replica host=lapdc.abmas.biz:389 - suffix="dc=abmas,dc=biz" - binddn="cn=updateuser,dc=abmas,dc=biz" - bindmethod=simple credentials=not24get - -access to attrs=sambaLMPassword,sambaNTPassword - by dn="cn=sambaadmin,dc=abmas,dc=biz" write - by * none - -replogfile /var/lib/ldap/replogfile - -directory /var/lib/ldap - -# Indices to maintain -index objectClass eq -index cn pres,sub,eq -index sn pres,sub,eq -index uid pres,sub,eq -index displayName pres,sub,eq -index uidNumber eq -index gidNumber eq -index memberUID eq -index sambaSID eq -index sambaPrimaryGroupSID eq -index sambaDomainName eq -index default sub -</screen> -</example> - -<example id="ch7-LDAP-slave"> -<title>LDAP Slave Configuration File &smbmdash; <filename>/etc/openldap/slapd.conf</filename></title> -<screen> -include /etc/openldap/schema/core.schema -include /etc/openldap/schema/cosine.schema -include /etc/openldap/schema/inetorgperson.schema -include /etc/openldap/schema/nis.schema -include /etc/openldap/schema/samba.schema - -pidfile /var/run/slapd/slapd.pid -argsfile /var/run/slapd/slapd.args - -database bdb -suffix "dc=abmas,dc=biz" -rootdn "cn=Manager,dc=abmas,dc=biz" - -# rootpw = not24get -rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV - -access to * - by dn=cn=updateuser,dc=abmas,dc=biz write - by * read - -updatedn cn=updateuser,dc=abmas,dc=biz -updateref ldap://massive.abmas.biz - -directory /var/lib/ldap - -# Indices to maintain -index objectClass eq -index cn pres,sub,eq -index sn pres,sub,eq -index uid pres,sub,eq -index displayName pres,sub,eq -index uidNumber eq -index gidNumber eq -index memberUID eq -index sambaSID eq -index sambaPrimaryGroupSID eq -index sambaDomainName eq -index default sub -</screen> -</example> - -<example id="ch7-massmbconfA"> -<title>Primary Domain Controller &smb.conf; File &smbmdash; Part A</title> -<smbconfblock> -<smbconfcomment>Global parameters</smbconfcomment> -<smbconfsection name="[global]"/> -<smbconfoption name="unix charset">LOCALE</smbconfoption> -<smbconfoption name="workgroup">MEGANET2</smbconfoption> -<smbconfoption name="passdb backend">ldapsam:ldap://massive.abmas.biz</smbconfoption> -<smbconfoption name="username map">/etc/samba/smbusers</smbconfoption> -<smbconfoption name="log level">1</smbconfoption> -<smbconfoption name="syslog">0</smbconfoption> -<smbconfoption name="log file">/var/log/samba/%m</smbconfoption> -<smbconfoption name="max log size">0</smbconfoption> -<smbconfoption name="smb ports">139</smbconfoption> -<smbconfoption name="name resolve order">wins bcast hosts</smbconfoption> -<smbconfoption name="time server">Yes</smbconfoption> -<smbconfoption name="printcap name">CUPS</smbconfoption> -<smbconfoption name="add user script">/opt/IDEALX/sbin/smbldap-useradd -m '%u'</smbconfoption> -<smbconfoption name="delete user script">/opt/IDEALX/sbin/smbldap-userdel '%u'</smbconfoption> -<smbconfoption name="add group script">/opt/IDEALX/sbin/smbldap-groupadd -p '%g'</smbconfoption> -<smbconfoption name="delete group script">/opt/IDEALX/sbin/smbldap-groupdel '%g'</smbconfoption> -<smbconfoption name="add user to group script">/opt/IDEALX/sbin/smbldap-groupmod -m '%g' '%u'</smbconfoption> -<smbconfoption name="delete user from group script">/opt/IDEALX/sbin/smbldap-groupmod -x '%g' '%u'</smbconfoption> -<smbconfoption name="set primary group script">/opt/IDEALX/sbin/smbldap-usermod -g '%g' '%u'</smbconfoption> -<smbconfoption name="add machine script">/opt/IDEALX/sbin/smbldap-useradd -w '%u'</smbconfoption> -<smbconfoption name="shutdown script">/var/lib/samba/scripts/shutdown.sh</smbconfoption> -<smbconfoption name="abort shutdown script">/sbin/shutdown -c</smbconfoption> -<smbconfoption name="logon script">scripts\logon.bat</smbconfoption> -<smbconfoption name="logon path">\\%L\profiles\%U</smbconfoption> -<smbconfoption name="logon drive">X:</smbconfoption> -<smbconfoption name="domain logons">Yes</smbconfoption> -<smbconfoption name="domain master">Yes</smbconfoption> -<smbconfoption name="wins support">Yes</smbconfoption> -<smbconfoption name="ldap suffix">dc=abmas,dc=biz</smbconfoption> -<smbconfoption name="ldap machine suffix">ou=People</smbconfoption> -<smbconfoption name="ldap user suffix">ou=People</smbconfoption> -<smbconfoption name="ldap group suffix">ou=Groups</smbconfoption> -<smbconfoption name="ldap idmap suffix">ou=Idmap</smbconfoption> -<smbconfoption name="ldap admin dn">cn=sambaadmin,dc=abmas,dc=biz</smbconfoption> -<smbconfoption name="idmap backend">ldap://massive.abmas.biz</smbconfoption> -<smbconfoption name="idmap uid">10000-20000</smbconfoption> -<smbconfoption name="idmap gid">10000-20000</smbconfoption> -<smbconfoption name="printing">cups</smbconfoption> -</smbconfblock> -</example> - -<example id="ch7-massmbconfB"> -<title>Primary Domain Controller &smb.conf; File &smbmdash; Part B</title> -<smbconfblock> -<smbconfsection name="[IPC$]"/> -<smbconfoption name="path">/tmp</smbconfoption> - -<smbconfsection name="[accounts]"/> -<smbconfoption name="comment">Accounting Files</smbconfoption> -<smbconfoption name="path">/data/accounts</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[service]"/> -<smbconfoption name="comment">Financial Services Files</smbconfoption> -<smbconfoption name="path">/data/service</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[pidata]"/> -<smbconfoption name="comment">Property Insurance Files</smbconfoption> -<smbconfoption name="path">/data/pidata</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[homes]"/> -<smbconfoption name="comment">Home Directories</smbconfoption> -<smbconfoption name="valid users">%S</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="browseable">No</smbconfoption> - -<smbconfsection name="[printers]"/> -<smbconfoption name="comment">SMB Print Spool</smbconfoption> -<smbconfoption name="path">/var/spool/samba</smbconfoption> -<smbconfoption name="guest ok">Yes</smbconfoption> -<smbconfoption name="printable">Yes</smbconfoption> -<smbconfoption name="browseable">No</smbconfoption> -</smbconfblock> -</example> - -<example id="ch7-massmbconfC"> -<title>Primary Domain Controller &smb.conf; File &smbmdash; Part C</title> -<smbconfblock> -<smbconfsection name="[apps]"/> -<smbconfoption name="comment">Application Files</smbconfoption> -<smbconfoption name="path">/apps</smbconfoption> -<smbconfoption name="admin users">bjones</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[netlogon]"/> -<smbconfoption name="comment">Network Logon Service</smbconfoption> -<smbconfoption name="path">/var/lib/samba/netlogon</smbconfoption> -<smbconfoption name="admin users">root, Administrator</smbconfoption> -<smbconfoption name="guest ok">Yes</smbconfoption> -<smbconfoption name="locking">No</smbconfoption> - -<smbconfsection name="[profiles]"/> -<smbconfoption name="comment">Profile Share</smbconfoption> -<smbconfoption name="path">/var/lib/samba/profiles</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="profile acls">Yes</smbconfoption> - -<smbconfsection name="[profdata]"/> -<smbconfoption name="comment">Profile Data Share</smbconfoption> -<smbconfoption name="path">/var/lib/samba/profdata</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="profile acls">Yes</smbconfoption> - -<smbconfsection name="[print$]"/> -<smbconfoption name="comment">Printer Drivers</smbconfoption> -<smbconfoption name="path">/var/lib/samba/drivers</smbconfoption> -<smbconfoption name="write list">root</smbconfoption> -<smbconfoption name="admin users">root, Administrator</smbconfoption> -</smbconfblock> -</example> - -<example id="ch7-slvsmbocnfA"> -<title>Backup Domain Controller &smb.conf; File &smbmdash; Part A</title> -<smbconfblock> -<smbconfcomment># Global parameters</smbconfcomment> -<smbconfsection name="[global]"/> -<smbconfoption name="unix charset">LOCALE</smbconfoption> -<smbconfoption name="workgroup">MEGANET2</smbconfoption> -<smbconfoption name="netbios name">BLDG1</smbconfoption> -<smbconfoption name="passdb backend">ldapsam:ldap://lapdc.abmas.biz</smbconfoption> -<smbconfoption name="username map">/etc/samba/smbusers</smbconfoption> -<smbconfoption name="log level">1</smbconfoption> -<smbconfoption name="syslog">0</smbconfoption> -<smbconfoption name="log file">/var/log/samba/%m</smbconfoption> -<smbconfoption name="max log size">50</smbconfoption> -<smbconfoption name="smb ports">139</smbconfoption> -<smbconfoption name="name resolve order">wins bcast hosts</smbconfoption> -<smbconfoption name="printcap name">CUPS</smbconfoption> -<smbconfoption name="show add printer wizard">No</smbconfoption> -<smbconfoption name="logon script">scripts\logon.bat</smbconfoption> -<smbconfoption name="logon path">\\%L\profiles\%U</smbconfoption> -<smbconfoption name="logon drive">X:</smbconfoption> -<smbconfoption name="domain logons">Yes</smbconfoption> -<smbconfoption name="os level">63</smbconfoption> -<smbconfoption name="domain master">No</smbconfoption> -<smbconfoption name="wins server">192.168.2.1</smbconfoption> -<smbconfoption name="ldap suffix">dc=abmas,dc=biz</smbconfoption> -<smbconfoption name="ldap machine suffix">ou=People</smbconfoption> -<smbconfoption name="ldap user suffix">ou=People</smbconfoption> -<smbconfoption name="ldap group suffix">ou=Groups</smbconfoption> -<smbconfoption name="ldap idmap suffix">ou=Idmap</smbconfoption> -<smbconfoption name="ldap admin dn">cn=sambaadmin,dc=abmas,dc=biz</smbconfoption> -<smbconfoption name="utmp">Yes</smbconfoption> -<smbconfoption name="idmap backend">ldap://massive.abmas.biz</smbconfoption> -<smbconfoption name="idmap uid">10000-20000</smbconfoption> -<smbconfoption name="idmap gid">10000-20000</smbconfoption> -<smbconfoption name="printing">cups</smbconfoption> - -<smbconfsection name="[accounts]"/> -<smbconfoption name="comment">Accounting Files</smbconfoption> -<smbconfoption name="path">/data/accounts</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[service]"/> -<smbconfoption name="comment">Financial Services Files</smbconfoption> -<smbconfoption name="path">/data/service</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -</smbconfblock> -</example> - -<example id="ch7-slvsmbocnfB"> -<title>Backup Domain Controller &smb.conf; File &smbmdash; Part B</title> -<smbconfblock> -<smbconfsection name="[pidata]"/> -<smbconfoption name="comment">Property Insurance Files</smbconfoption> -<smbconfoption name="path">/data/pidata</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[homes]"/> -<smbconfoption name="comment">Home Directories</smbconfoption> -<smbconfoption name="valid users">%S</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="browseable">No</smbconfoption> - -<smbconfsection name="[printers]"/> -<smbconfoption name="comment">SMB Print Spool</smbconfoption> -<smbconfoption name="path">/var/spool/samba</smbconfoption> -<smbconfoption name="guest ok">Yes</smbconfoption> -<smbconfoption name="printable">Yes</smbconfoption> -<smbconfoption name="browseable">No</smbconfoption> - -<smbconfsection name="[apps]"/> -<smbconfoption name="comment">Application Files</smbconfoption> -<smbconfoption name="path">/apps</smbconfoption> -<smbconfoption name="admin users">bjones</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> - -<smbconfsection name="[netlogon]"/> -<smbconfoption name="comment">Network Logon Service</smbconfoption> -<smbconfoption name="path">/var/lib/samba/netlogon</smbconfoption> -<smbconfoption name="guest ok">Yes</smbconfoption> -<smbconfoption name="locking">No</smbconfoption> - -<smbconfsection name="[profiles]"/> -<smbconfoption name="comment">Profile Share</smbconfoption> -<smbconfoption name="path">/var/lib/samba/profiles</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="profile acls">Yes</smbconfoption> - -<smbconfsection name="[profdata]"/> -<smbconfoption name="comment">Profile Data Share</smbconfoption> -<smbconfoption name="path">/var/lib/samba/profdata</smbconfoption> -<smbconfoption name="read only">No</smbconfoption> -<smbconfoption name="profile acls">Yes</smbconfoption> -</smbconfblock> -</example> - - <sect2> - <title>Key Points Learned</title> - - <itemizedlist> - <listitem><para> - <indexterm><primary>LDAP</primary></indexterm><indexterm><primary>BDC</primary></indexterm> - Where Samba is used as a domain controller, the use of LDAP is an - essential component to permit the use of BDCs. - </para></listitem> - - <listitem><para> - <indexterm><primary>wide-area</primary></indexterm> - Replication of the LDAP master server to create a network of BDCs - is an important mechanism for limiting WAN traffic. - </para></listitem> - - <listitem><para> - Network administration presents many complex challenges, most of which - can be satisfied by good design but that also require sound communication - and unification of management practices. This can be highly challenging in - a large, globally distributed network. - </para></listitem> - - <listitem><para> - Roaming profiles must be contained to the local network segment. Any - departure from this may clog wide-area arteries and slow legitimate network - traffic to a crawl. - </para></listitem> - </itemizedlist> - - </sect2> - - <figure id="chap7net"> - <title>Network Topology &smbmdash; 2000 User Complex Design A</title> - <imagefile scale="80">chap7-net-Ar</imagefile> - </figure> - - <figure id="chap7net2"> - <title>Network Topology &smbmdash; 2000 User Complex Design B</title> - <imagefile scale="80">chap7-net2-Br</imagefile> - </figure> - -</sect1> - -<sect1> - <title>Questions and Answers</title> - - <para> - There is much rumor and misinformation regarding the use of MS Windows networking protocols. - These questions are just a few of those frequently asked. - </para> - - <qandaset defaultlabel="chap07qa" type="number"> - <qandaentry> - <question> - - <para> - <indexterm><primary>DHCP</primary></indexterm> - <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> - Is it true that DHCP uses lots of WAN bandwidth? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>DHCP</primary><secondary>Relay Agent</secondary></indexterm> - <indexterm><primary>routers</primary></indexterm> - <indexterm><primary>DHCP</primary><secondary>servers</secondary></indexterm> - It is a smart practice to localize DHCP servers on each network segment. As a - rule, there should be two DHCP servers per network segment. This means that if - one server fails, there is always another to service user needs. DHCP requests use - only UDP broadcast protocols. It is possible to run a DHCP Relay Agent on network - routers. This makes it possible to run fewer DHCP servers. - </para> - - <para> - <indexterm><primary>DHCP</primary><secondary>request</secondary></indexterm> - <indexterm><primary>DHCP</primary><secondary>traffic</secondary></indexterm> - A DHCP network address request and confirmation usually results in about six UDP packets. - The packets are from 60 to 568 bytes in length. Let us consider a site that has 300 DHCP - clients and that uses a 24-hour IP address lease. This means that all clients renew - their IP address lease every 24 hours. If we assume an average packet length equal to the - maximum (just to be on the safe side), and we have a 128 Kb/sec wide-area connection, - how significant would the DHCP traffic be if all of it were to use DHCP Relay? - </para> - - <para> - I must stress that this is a bad design, but here is the calculation: -<screen> -Daily Network Capacity: 128,000 (Kbits/s) / 8 (bits/byte) - x 3600 (sec/hr) x 24 (hrs/day)= 2288 Mbytes/day. - -DHCP traffic: 300 (clients) x 6 (packets) - x 512 (bytes/packet) = 0.9 Mbytes/day. -</screen> - From this can be seen that the traffic impact would be minimal. - </para> - - <para> - <indexterm><primary>DNS</primary><secondary>Dynamic</secondary></indexterm> - <indexterm><primary>DHCP</primary></indexterm> - Even when DHCP is configured to do DNS update (dynamic DNS) over a wide-area link, - the impact of the update is no more than the DHCP IP address renewal traffic and thus - still insignificant for most practical purposes. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - <indexterm><primary>background communication</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>master/slave</secondary><tertiary>background communication</tertiary></indexterm> - How much background communication takes place between a master LDAP server and its slave LDAP servers? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>slurpd</primary></indexterm> - The process that controls the replication of data from the master LDAP server to the slave LDAP - servers is called <command>slurpd</command>. The <command>slurpd</command> remains nascent (quiet) - until an update must be propagated. The propagation traffic per LDAP slave to update (add/modify/delete) - two user accounts requires less than 10KB traffic. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - LDAP has a database. Is LDAP not just a fancy database front end? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>database</primary></indexterm> - <indexterm><primary>LDAP</primary><secondary>database</secondary></indexterm> - <indexterm><primary>SQL</primary></indexterm> - <indexterm><primary>transactional</primary></indexterm> - LDAP does store its data in a database of sorts. In fact, the LDAP backend is an application-specific - data storage system. This type of database is indexed so that records can be rapidly located, but the - database is not generic and can be used only in particular pre-programmed ways. General external - applications do not gain access to the data. This type of database is used also by SQL servers. Both - an SQL server and an LDAP server provide ways to access the data. An SQL server has a transactional - orientation and typically allows external programs to perform ad hoc queries, even across data tables. - An LDAP front end is a purpose-built tool that has a search orientation that is designed around specific - simple queries. The term <constant>database</constant> is heavily overloaded and thus much misunderstood. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - <indexterm><primary>OpenLDAP</primary></indexterm> - Can Active Directory obtain account information from an OpenLDAP server? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>meta-directory</primary></indexterm> - No, at least not directly. It is possible to provision Active Directory from and/or to an OpenLDAP - database through use of a metadirectory server. Microsoft MMS (now called MIIS) can interface - to OpenLDAP using standard LDAP queries and updates. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - What are the parts of a roaming profile? How large is each part? - </para> - - </question> - <answer> - - <para><indexterm> - <primary>roaming profile</primary> - </indexterm> - A roaming profile consists of - </para> - - <itemizedlist> - <listitem><para> - Desktop folders such as <constant>Desktop</constant>, <constant>My Documents</constant>, - <constant>My Pictures</constant>, <constant>My Music</constant>, <constant>Internet Files</constant>, - <constant>Cookies</constant>, <constant>Application Data</constant>, - <constant>Local Settings,</constant> and more. See <link linkend="happy"/>, <link linkend="XP-screen001"/>. - </para> - - <para> - <indexterm><primary>folder redirection</primary></indexterm> - Each of these can be anywhere from a few bytes to gigabytes in capacity. Fortunately, all - such folders can be redirected to network drive resources. See <link linkend="redirfold"/> - for more information regarding folder redirection. - </para></listitem> - - <listitem><para> - A static or rewritable portion that is typically only a few files (2-5 KB of information). - </para></listitem> - - <listitem><para> - <indexterm><primary>NTUSER.DAT</primary></indexterm> - <indexterm><primary>HKEY_LOCAL_USER</primary></indexterm> - The registry load file that modifies the <constant>HKEY_LOCAL_USER</constant> hive. This is - the <filename>NTUSER.DAT</filename> file. It can be from 0.4 to 1.5 MB. - </para></listitem> - </itemizedlist> - - <para> - <indexterm><primary>Microsoft Outlook</primary><secondary>PST files</secondary></indexterm> - Microsoft Outlook PST files may be stored in the <constant>Local Settings\Application Data</constant> - folder. It can be up to 2 GB in size per PST file. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - Can the <constant>My Documents</constant> folder be stored on a network drive? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>UNC name</primary></indexterm> - <indexterm><primary>Universal Naming Convention</primary><see>UNC name</see></indexterm> - Yes. More correctly, such folders can be redirected to network shares. No specific network drive - connection is required. Registry settings permit this to be redirected directly to a UNC (Universal - Naming Convention) resource, though it is possible to specify a network drive letter instead of a - UNC name. See <link linkend="redirfold"/>. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - <indexterm><primary>wide-area</primary></indexterm> - <indexterm><primary>network</primary><secondary>bandwidth</secondary></indexterm> - <indexterm><primary>WINS</primary></indexterm> - How much WAN bandwidth does WINS consume? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>NetBIOS</primary><secondary>name cache</secondary></indexterm> - <indexterm><primary>WINS server</primary></indexterm> - <indexterm><primary>domain replication</primary></indexterm> - MS Windows clients cache information obtained from WINS lookups in a local NetBIOS name cache. - This keeps WINS lookups to a minimum. On a network with 3500 MS Windows clients and a central WINS - server, the total bandwidth demand measured at the WINS server, averaged over an 8-hour working day, - was less than 30 KB/sec. Analysis of network traffic over a 6-week period showed that the total - of all background traffic consumed about 11 percent of available bandwidth over 64 Kb/sec links. - Background traffic consisted of domain replication, WINS queries, DNS lookups, and authentication - traffic. Each of 11 branch offices had a 64 Kb/sec wide-area link, with a 1.5 Mb/sec main connection - that aggregated the branch office connections plus an Internet connection. - </para> - - <para> - In conclusion, the total load afforded through WINS traffic is again marginal to total operational - usage &smbmdash; as it should be. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - How many BDCs should I have? What is the right number of Windows clients per server? - </para> - - </question> - <answer> - - <para> - It is recommended to have at least one BDC per network segment, including the segment served - by the PDC. Actual requirements vary depending on the working load on each of the BDCs and the - load demand pattern of client usage. I have seen sites that function without problem with 200 - clients served by one BDC, and yet other sites that had one BDC per 20 clients. In one particular - company, there was a drafting office that had 30 CAD/CAM operators served by one server, a print - server; and an application server. While all three were BDCs, typically only the print server would - service network logon requests after the first 10 users had started to use the network. This was - a reflection of the service load placed on both the application server and the data server. - </para> - - <para> - As unsatisfactory as the answer might sound, it all depends on network and server load - characteristics. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - <indexterm><primary>NIS server</primary></indexterm><indexterm><primary>LDAP</primary></indexterm> - I've heard that you can store NIS accounts in LDAP. Is LDAP not just a smarter way to - run an NIS server? - </para> - - </question> - <answer> - - <para> - The correct answer to both questions is yes. But do understand that an LDAP server has - a configurable schema that can store far more information for many more purposes than - just NIS. - </para> - - </answer> - </qandaentry> - - <qandaentry> - <question> - - <para> - Can I use NIS in place of LDAP? - </para> - - </question> - <answer> - - <para> - <indexterm><primary>NIS</primary></indexterm> - <indexterm><primary>NIS schema</primary></indexterm> - No. The NIS database does not have provision to store Microsoft encrypted passwords and does not deal - with the types of data necessary for interoperability with Microsoft Windows networking. The use - of LDAP with Samba requires the use of a number of schemas, one of which is the NIS schema, but also - a Samba-specific schema extension. - </para> - -</answer> - </qandaentry> - - </qandaset> -</sect1> - -</chapter> - |