NetBSD/share/man/man7/users.7

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.Dd April 2, 2020
.Dt USERS 7
.Os
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.Sh NAME
.Nm users
.Nd standard user account names
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.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.
.Bl -tag -width ".Em _tcpdump"
.It 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 .
.Pp
Secondary groups:
.Em guest ,
.Em kmem ,
.Em nvmm ,
.Em operator ,
.Em staff ,
.Em sys ,
.Em tty .
.It Em toor
Like
.Em root ,
this is the super-user with uid 0, but with no secondary group
memberships.
.Pp
Historically,
.Em root
had a login shell of
.Pa /bin/csh
while
.Em toor
had a login shell of
.Pa /bin/sh .
However, today both default to
.Pa /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.
.It Em daemon
Historic user for general daemonic activity.
.Pp
Owner of
.Pa /var/msgs ;
see
.Xr msgs 1 .
Used only by
.Xr rpcbind 8 ,
with the
.Fl s
flag.
.It Em operator
Historic user.
Unused in modern
.Nx .
.It Em bin
Historic user.
Unused in modern
.Nx .
.It Em games
Owner of high-score files and other shared files for games.
.It Em postfix
Pseudo-user for use by the
.Xr postfix 1
mail transfer agent.
.It Em named
Pseudo-user for use by the
.Xr named 8
DNS nameserver daemon.
.It Em ntpd
Pseudo-user for use by the
.Xr ntpd 8
network time protocol daemon.
.It Em sshd
Pseudo-user for use by the
.Xr sshd 8
secure shell daemon.
.It Em _pflogd
Pseudo-user for use by the
.Xr pflogd 8
log daemon with the
.Xr pf 4
packet filter.
.It Em _rwhod
Pseudo-user for use by the
.Xr rwhod 8
system status daemon.
.It 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 .
.It Em _timedc
Pseudo-user for use by the
.Xr timedc 8
tool to communicate with the
.Xr timed 8
time server daemon.
.It Em _sdpd
Pseudo-user for use by the
.Xr sdpd 8
Bluetooth service discovery protocol daemon.
.It Em _httpd
Pseudo-user for use by the
.Xr httpd 8 Pq bozohttpd
web server.
.It Em _mdnsd
Pseudo-user for use by the
.Xr mdnsd 8
multicast DNS and DNS service discovery daemon.
.It 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 .
.It Em _tcpdump
Pseudo-user for use by the
.Xr tcpdump 8
network traffic dumper and analyzer.
.It Em _tss
Pseudo-user for use by the
.Xr tcsd 8
.Sq Trusted Computing
daemon TPM to manage a TPM.
.It Em _dhcpcd
Pseudo-user for use by the
.Xr dhcpcd 8
DHCP Client Daemon.
.It Em _rtadvd
Pseudo-user for use by the
.Xr rtadvd 8
IPv6 network router advertisement daemon.
.It Em _unbound
Pseudo-user for the
.Xr unbound 8
recursive DNS resolver.
.It Em _nsd
Pseudo-user for the
.Xr nsd 8
authoritative DNS nameserver.
.It Em uucp
Pseudo-user for use by historic UUCP software, available now in
.Xr pkgsrc 7 .
.It 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
.Pp
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