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 $NetBSD: users.7,v 1.5 2020/04/02 20:57:20 roy Exp $

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.Dd April 2, 2020
.Dt USERS 7
.Os
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.Sh NAME
.Nm users
.Nd standard user account names
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.Sh DESCRIPTION
A standard
.Nx
installation has the following user account names:
 These are currently sorted by uid; perhaps they should be sorted
 lexicographically by name instead.
l -tag -width ".Em _tcpdump" t Em root The super-user, uid 0, with the highest administrative privileges.
Normally not used for login directly, only via
.Xr su 1
or equivalent by users in the
.Em wheel
group; see
.Xr groups 7 .

p
Secondary groups:
.Em guest ,
.Em kmem ,
.Em nvmm ,
.Em operator ,
.Em staff ,
.Em sys ,
.Em tty .
t Em toor Like
.Em root ,
this is the super-user with uid 0, but with no secondary group
memberships.

p
Historically,
.Em root
had a login shell of

a /bin/csh
while
.Em toor
had a login shell of

a /bin/sh .
However, today both default to

a /bin/sh .
This user account name is not used for anything in
.Nx ;
it is purely a convenience for actual users.
 Maybe we should just remove this.
t Em daemon Historic user for general daemonic activity.

p
Owner of

a /var/msgs ;
see
.Xr msgs 1 .
Used only by
.Xr rpcbind 8 ,
with the
.Fl s
flag.
t Em operator Historic user.
Unused in modern
.Nx .
t Em bin Historic user.
Unused in modern
.Nx .
t Em games Owner of high-score files and other shared files for games.
t Em postfix Pseudo-user for use by the
.Xr postfix 1
mail transfer agent.
t Em named Pseudo-user for use by the
.Xr named 8
DNS nameserver daemon.
t Em ntpd Pseudo-user for use by the
.Xr ntpd 8
network time protocol daemon.
t Em sshd Pseudo-user for use by the
.Xr sshd 8
secure shell daemon.
t Em _pflogd Pseudo-user for use by the
.Xr pflogd 8
log daemon with the
.Xr pf 4
packet filter.
t Em _rwhod Pseudo-user for use by the
.Xr rwhod 8
system status daemon.
t Em _proxy Pseudo-user for use by the
.Xr ftp-proxy 8
and
.Xr tftp-proxy 8
proxy daemons with packet filters such as
.Xr pf 4
or
.Xr ipnat 4 .
t Em _timedc Pseudo-user for use by the
.Xr timedc 8
tool to communicate with the
.Xr timed 8
time server daemon.
t Em _sdpd Pseudo-user for use by the
.Xr sdpd 8
Bluetooth service discovery protocol daemon.
t Em _httpd Pseudo-user for use by the
.Xr httpd 8 Pq bozohttpd
web server.
t Em _mdnsd Pseudo-user for use by the
.Xr mdnsd 8
multicast DNS and DNS service discovery daemon.
t Em _tests Pseudo-user for use by
.Xr atf 7
automatic tests that request to run unprivileged.
Default value for the
.Sq unprivileged-user
configuration variable; see
.Xr tests 7 .
t Em _tcpdump Pseudo-user for use by the
.Xr tcpdump 8
network traffic dumper and analyzer.
t Em _tss Pseudo-user for use by the
.Xr tcsd 8
.Sq Trusted Computing
daemon TPM to manage a TPM.
t Em _dhcpcd Pseudo-user for use by the
.Xr dhcpcd 8
DHCP Client Daemon.
t Em _rtadvd Pseudo-user for use by the
.Xr rtadvd 8
IPv6 network router advertisement daemon.
t Em _unbound Pseudo-user for the
.Xr unbound 8
recursive DNS resolver.
t Em _nsd Pseudo-user for the
.Xr nsd 8
authoritative DNS nameserver.
t Em uucp Pseudo-user for use by historic UUCP software, available now in
.Xr pkgsrc 7 .
t Em nobody Traditional pseudo-user used for dropping privileges.
Modern practice is to assign to each different daemon its own separate
pseudo-user account and group so that if one daemon is compromised it
does not compromise all the other daemons.
.El

p
All new standard
.Nx
pseudo-user account names should begin with an underscore
.Sq "_"
to distinguish them from accounts that real users might add, and should
have a primary group of the same name; real users should accordingly
avoid such account names.
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.Sh SEE ALSO
.Xr groups 7