Throughout BLFS, many packages install programs that run as daemons
or in some way should have a user or group name assigned. Generally
these names are used to map a user ID (uid) or group ID (gid) for
system use. Generally the specific uid or gid numbers used by these
applications are not significant. The exception of course, is that
root has a uid and gid of 0 (zero)
that is indeed special. The uid values are stored in /etc/passwd and the gid values are found in
/etc/group.
Customarily, Unix systems classify users and groups into two
categories: system users and regular users. The system users and
groups are given low numbers and regular users and groups have
numeric values greater than all the system values. The cutoff for
these numbers is found in two parameters in the /etc/login.defs configuration file. The default
UID_MIN value is 1000 and the default GID_MIN value is 1000. If a
specific uid or gid value is not specified when creating a user with
useradd or a group with
groupadd the values
assigned will always be above these cutoff values.
Additionally, the Linux Standard Base recommends that system uid and gid values should be below 100.
Below is a table of suggested uid/gid values used in BLFS beyond those defined in a base LFS installation. These can be changed as desired, but provide a suggested set of consistent values.
Table 3.1. UID/GID Suggested Values
| Name | uid | gid |
|---|---|---|
| bin | 1 | |
| lp | 9 | |
| adm | 16 | |
| atd | 17 | 17 |
| messagebus | 18 | 18 |
| lpadmin | 19 | |
| named | 20 | 20 |
| gdm | 21 | 21 |
| fcron | 22 | 22 |
| systemd-journal | 23 | 23 |
| apache | 25 | 25 |
| smmsp | 26 | 26 |
| polkitd | 27 | 27 |
| rpc | 28 | 28 |
| exim | 31 | 31 |
| postfix | 32 | 32 |
| postdrop | 33 | |
| sendmail | 34 | |
| 34 | ||
| vmailman | 35 | 35 |
| news | 36 | 36 |
| kdm | 37 | 37 |
| fetchmail | 38 | |
| mysql | 40 | 40 |
| postgres | 41 | 41 |
| dovecot | 42 | 42 |
| dovenull | 43 | 43 |
| ftp | 45 | 45 |
| proftpd | 46 | 46 |
| vsftpd | 47 | 47 |
| rsyncd | 48 | 48 |
| sshd | 50 | 50 |
| stunnel | 51 | 51 |
| dhcpcd | 52 | 52 |
| svn | 56 | 56 |
| svntest | 57 | |
| git | 58 | 58 |
| games | 60 | 60 |
| kvm | 61 | |
| wireshark | 62 | |
| lightdm | 63 | 63 |
| sddm | 64 | 64 |
| lightdm | 65 | 65 |
| scanner | 70 | |
| colord | 71 | 71 |
| systemd-bus-proxy | 72 | 72 |
| systemd-journal-gateway | 73 | 73 |
| systemd-journal-remote | 74 | 74 |
| systemd-journal-upload | 75 | 75 |
| systemd-network | 76 | 76 |
| systemd-resolve | 77 | 77 |
| systemd-timesync | 78 | 78 |
| systemd-coredump | 79 | 79 |
| uuidd | 80 | 80 |
| systemd-oom | 81 | 81 |
| ldap | 83 | 83 |
| avahi | 84 | 84 |
| avahi-autoipd | 85 | 85 |
| netdev | 86 | |
| ntp | 87 | 87 |
| unbound | 88 | 88 |
| plugdev | 90 | |
| wheel | 97 | |
| anonymous | 98 | |
| nobody | 99 | |
| nogroup | 99 |
One value that is missing is 65534. This value is customarily
assigned to the user nobody and group
nogroup and is unnecessary.
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