[17b7723] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
---|
| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
|
---|
| 3 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
|
---|
| 4 | <!ENTITY % general-entities SYSTEM "../../general.ent">
|
---|
| 5 | %general-entities;
|
---|
| 6 | ]>
|
---|
| 7 |
|
---|
| 8 | <sect1 id="postlfs-users-groups" xreflabel="About System Users and Groups">
|
---|
| 9 | <?dbhtml filename="users.html"?>
|
---|
| 10 |
|
---|
| 11 | <sect1info>
|
---|
| 12 | <othername>$LastChangedBy$</othername>
|
---|
| 13 | <date>$Date$</date>
|
---|
| 14 | </sect1info>
|
---|
| 15 |
|
---|
| 16 | <title>About System Users and Groups</title>
|
---|
| 17 |
|
---|
| 18 | <indexterm zone="postlfs-users-groups">
|
---|
| 19 | <primary sortas="e-etc-passwd">/etc/passwd</primary>
|
---|
| 20 | </indexterm>
|
---|
| 21 |
|
---|
| 22 | <indexterm zone="postlfs-users-groups">
|
---|
| 23 | <primary sortas="e-etc-group">/etc/group</primary>
|
---|
| 24 | </indexterm>
|
---|
| 25 |
|
---|
| 26 | <indexterm zone="postlfs-users-groups">
|
---|
| 27 | <primary sortas="e-etc-login.defs">/etc/login.defs</primary>
|
---|
| 28 | </indexterm>
|
---|
| 29 |
|
---|
| 30 | <para>Throughout BLFS, there are many packages that install programs that
|
---|
| 31 | run as daemons or in some way should have a user or group name
|
---|
| 32 | assigned. Generally these names are used to map a user ID (uid) or group
|
---|
| 33 | ID (gid) for system use. Generally the specific uid or gid numbers used
|
---|
| 34 | by these applications are not significant. The exception, of course is
|
---|
| 35 | that root has a uid and gid of 0 (zero) that is indeed special. The uid
|
---|
| 36 | values are stored in <filename>/etc/passwd</filename> and the gid values
|
---|
| 37 | are found in <filename>/etc/group</filename>.
|
---|
| 38 | </para>
|
---|
| 39 |
|
---|
| 40 | <para>Customarily, Unix systems classify users and groups into two
|
---|
| 41 | categories: system users and regular users. The system users and groups are
|
---|
| 42 | given low numbers and regular users and groups have numeric values greater
|
---|
| 43 | than all the system values. The cutoff for these numbers is found in two
|
---|
| 44 | parameters in the <filename>/etc/login.defs</filename> configuration file.
|
---|
| 45 | The default UID_MIN value is 1000 and the default GID_MIN value is 100. If a
|
---|
| 46 | specific uid or gid value is not specified when creating a user with
|
---|
| 47 | <command>useradd</command> or a group with <command>groupadd</command> the values
|
---|
| 48 | assigned will always be above these cutoff values.</para>
|
---|
| 49 |
|
---|
| 50 | <para>Additionally, the
|
---|
| 51 | <ulink url='http://refspecs.freestandards.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/usernames.html'>
|
---|
| 52 | Linux Standards Base</ulink> recommends that system uid and gid values should be
|
---|
| 53 | below 100.</para>
|
---|
| 54 |
|
---|
| 55 | <para>Below is a table of suggested uid/gid values used in BLFS. These can
|
---|
| 56 | be changed as desired, but provide a suggested set of consistent values.</para>
|
---|
| 57 |
|
---|
| 58 | <table id="uidgid" class='uidvalues'>
|
---|
| 59 | <title>UID/GID Suggested Values</title>
|
---|
| 60 | <tgroup cols='3' colsep='0' rowsep='0'>
|
---|
| 61 | <thead>
|
---|
| 62 | <row><entry>Name</entry><entry>uid</entry><entry>gid</entry></row>
|
---|
| 63 | </thead>
|
---|
| 64 | <tbody>
|
---|
| 65 | <row><entry>bin </entry><entry> 1</entry><entry> 1</entry></row>
|
---|
| 66 | <row><entry>lp </entry><entry> 9</entry><entry> </entry></row>
|
---|
| 67 | <row><entry>usb </entry><entry> </entry><entry>14</entry></row>
|
---|
| 68 | <row><entry>named </entry><entry>20</entry><entry>20</entry></row>
|
---|
| 69 | <row><entry>gdm </entry><entry>21</entry><entry>21</entry></row>
|
---|
| 70 | <row><entry>fcron </entry><entry>22</entry><entry>22</entry></row>
|
---|
| 71 | <row><entry>apache </entry><entry>25</entry><entry>25</entry></row>
|
---|
[b785ab29] | 72 | <row><entry>smmsp </entry><entry>26</entry><entry>26</entry></row>
|
---|
[17b7723] | 73 | <row><entry>courier </entry><entry>30</entry><entry>30</entry></row>
|
---|
| 74 | <row><entry>exim </entry><entry>31</entry><entry>31</entry></row>
|
---|
| 75 | <row><entry>postfix </entry><entry>32</entry><entry>32</entry></row>
|
---|
| 76 | <row><entry>postdrop</entry><entry> </entry><entry>33</entry></row>
|
---|
| 77 | <row><entry>sendmail</entry><entry>34</entry><entry> </entry></row>
|
---|
| 78 | <row><entry>mail </entry><entry> </entry><entry>34</entry></row>
|
---|
| 79 | <row><entry>vmailman</entry><entry>35</entry><entry>35</entry></row>
|
---|
| 80 | <row><entry>news </entry><entry>36</entry><entry>36</entry></row>
|
---|
| 81 | <row><entry>mysql </entry><entry>40</entry><entry>40</entry></row>
|
---|
| 82 | <row><entry>postgres</entry><entry>41</entry><entry> </entry></row>
|
---|
| 83 | <row><entry>ftp </entry><entry>45</entry><entry>45</entry></row>
|
---|
| 84 | <row><entry>proftpd </entry><entry>46</entry><entry>46</entry></row>
|
---|
| 85 | <row><entry>vsftpd </entry><entry>47</entry><entry>47</entry></row>
|
---|
| 86 | <row><entry>rsyncd </entry><entry>48</entry><entry>48</entry></row>
|
---|
| 87 | <row><entry>sshd </entry><entry>50</entry><entry>50</entry></row>
|
---|
| 88 | <row><entry>stunnel </entry><entry>51</entry><entry>51</entry></row>
|
---|
| 89 | <row><entry>svn </entry><entry>56</entry><entry>56</entry></row>
|
---|
[b785ab29] | 90 | <row><entry>svntest </entry><entry> </entry><entry>57</entry></row>
|
---|
[17b7723] | 91 | <row><entry>games </entry><entry>60</entry><entry>60</entry></row>
|
---|
[b785ab29] | 92 | <row><entry>anonymous</entry><entry>98</entry><entry> </entry></row>
|
---|
[17b7723] | 93 | <row><entry>nobody </entry><entry>99</entry><entry> </entry></row>
|
---|
| 94 | <row><entry>nogroup </entry><entry> </entry><entry>99</entry></row>
|
---|
| 95 | </tbody>
|
---|
| 96 | </tgroup>
|
---|
| 97 | </table>
|
---|
| 98 |
|
---|
| 99 | <para>One value that is missing is 65534. This value is customarily assigned
|
---|
| 100 | to the user <systemitem class="username">nobody</systemitem> and group
|
---|
| 101 | <systemitem class="groupname">nogroup</systemitem> and is unnecessary. The
|
---|
| 102 | issue is explained in more detail in the first note in the <xref
|
---|
| 103 | linkend='nfs-utils-install'/> section.</para>
|
---|
| 104 |
|
---|
| 105 | </sect1>
|
---|