NAME¶
hostname - show or set the system's host name
domainname - show or set the system's NIS/YP domain name
ypdomainname - show or set the system's NIS/YP domain name
nisdomainname - show or set the system's NIS/YP domain name
dnsdomainname - show the system's DNS domain name
SYNOPSIS¶
hostname [
-v] [
-a|--alias] [
-d|--domain]
[
-f|--fqdn|--long] [
-A|--all-fqdns] [
-i|--ip-address]
[
-I|--all-ip-addresses] [
-s|--short] [
-y|--yp|--nis]
hostname [
-v] [
-b|--boot] [
-F|--file filename]
[
hostname]
hostname [
-v] [
-h|--help] [
-V|--version]
domainname [
nisdomain] [
-F file]
ypdomainname [
nisdomain] [
-F file]
nisdomainname [
nisdomain] [
-F file]
dnsdomainname [
-v]
DESCRIPTION¶
Hostname is used to display the system's DNS name, and to display or set
its hostname or NIS domain name.
GET NAME¶
When called without any arguments, the program displays the current names:
hostname will print the name of the system as returned by the
gethostname(2) function.
domainname will print the NIS domainname of the system.
domainname
uses the
gethostname(2) function, while
ypdomainname and
nisdomainname use the
yp_get_default_domain(3).
dnsdomainname will print the domain part of the FQDN (Fully Qualified
Domain Name). The complete FQDN of the system is returned with
hostname
--fqdn (but see the warnings in section
THE FQDN below).
SET NAME¶
When called with one argument or with the
--file option, the commands set
the host name or the NIS/YP domain name.
hostname uses the
sethostname(2) function, while all of the three
domainname,
ypdomainname and
nisdomainname use
setdomainname(2).
Note, that this is effective only until the next reboot. Edit /etc/hostname
for permanent change.
Note, that only the super-user can change the names.
It is not possible to set the FQDN or the DNS domain name with the
dnsdomainname command (see
THE FQDN below).
The host name is usually set once at system startup in
/etc/init.d/hostname.sh (normally by reading the contents of a file
which contains the host name, e.g.
/etc/hostname).
THE FQDN¶
You can't change the FQDN (as returned by
hostname --fqdn) or the DNS
domain name (as returned by
dnsdomainname) with this command. The FQDN
of the system is the name that the
resolver(3) returns for the host
name.
Technically: The FQDN is the name
getaddrinfo(3) returns for the host
name returned by
gethostname(2). The DNS domain name is the part after
the first dot.
Therefore it depends on the configuration (usually in
/etc/host.conf) how
you can change it. Usually (if the hosts file is parsed before DNS or NIS) you
can change it in
/etc/hosts.
If a machine has multiple network interfaces/addresses or is used in a mobile
environment, then it may either have multiple FQDNs/domain names or none at
all. Therefore avoid using
hostname --fqdn,
hostname --domain
and
dnsdomainname.
hostname --ip-address is subject to the same
limitations so it should be avoided as well.
OPTIONS¶
- -a, --alias
- Display the alias name of the host (if used). This option
is deprecated and should not be used anymore.
- -A, --all-fqdns
- Displays all FQDNs of the machine. This option enumerates
all configured network addresses on all configured network interfaces, and
translates them to DNS domain names. Addresses that cannot be translated
(i.e. because they do not have an appropriate reverse DNS entry) are
skipped. Note that different addresses may resolve to the same name,
therefore the output may contain duplicate entries. Do not make any
assumptions about the order of the output.
- -b, --boot
- Always set a hostname; this allows the file specified by
-F to be non-existant or empty, in which case the default hostname
localhost will be used if none is yet set.
- -d, --domain
- Display the name of the DNS domain. Don't use the command
domainname to get the DNS domain name because it will show the NIS
domain name and not the DNS domain name. Use dnsdomainname instead.
See the warnings in section THE FQDN above, and avoid using this
option.
- -f, --fqdn, --long
- Display the FQDN (Fully Qualified Domain Name). A FQDN
consists of a short host name and the DNS domain name. Unless you are
using bind or NIS for host lookups you can change the FQDN and the DNS
domain name (which is part of the FQDN) in the /etc/hosts file. See
the warnings in section THE FQDN above, and avoid using this
option; use hostname --all-fqdns instead.
- -F, --file filename
- Read the host name from the specified file. Comments (lines
starting with a `#') are ignored.
- -i, --ip-address
- Display the network address(es) of the host name. Note that
this works only if the host name can be resolved. Avoid using this option;
use hostname --all-ip-addresses instead.
- -I, --all-ip-addresses
- Display all network addresses of the host. This option
enumerates all configured addresses on all network interfaces. The
loopback interface and IPv6 link-local addresses are omitted. Contrary to
option -i, this option does not depend on name resolution. Do not
make any assumptions about the order of the output.
- -s, --short
- Display the short host name. This is the host name cut at
the first dot.
- -v, --verbose
- Be verbose and tell what's going on.
- -V, --version
- Print version information on standard output and exit
successfully.
- -y, --yp, --nis
- Display the NIS domain name. If a parameter is given (or
--file name ) then root can also set a new NIS domain.
- -h, --help
- Print a usage message and exit.
NOTES¶
The address families
hostname tries when looking up the FQDN, aliases and
network addresses of the host are determined by the configuration of your
resolver. For instance, on GNU Libc systems, the resolver can be instructed to
try IPv6 lookups first by using the
inet6 option in
/etc/resolv.conf.
FILES¶
/etc/hosts
/etc/hostname Historically this file was supposed to only contain the
hostname and not the full canonical FQDN. Nowadays most software is able to
cope with a full FQDN here.
AUTHORS¶
Peter Tobias, <tobias@et-inf.fho-emden.de>
Bernd Eckenfels, <net-tools@lina.inka.de> (NIS and manpage).
Michael Meskes, <meskes@debian.org>