domainname

HOSTNAME(1)                Linux Programmer's Manual               HOSTNAME(1)



NAME
       hostname - show or set the system's host name
       domainname - show or set the system's NIS/YP domain name
       dnsdomainname - show the system's DNS domain name
       nisdomainname - show or set system's NIS/YP domain name
       ypdomainname - show or set the system's NIS/YP domain name


SYNOPSIS
       hostname [-v] [-a] [--alias] [-d] [--domain] [-f] [--fqdn] [-A] [--all-
       fqdns] [-i] [--ip-address] [-I] [--all-ip-addresses] [--long] [-s]
       [--short] [-y] [--yp] [--nis]


       hostname [-v] [-F filename] [--file filename] [hostname]


       domainname [-v] [-F filename] [--file filename] [name]


       nodename [-v] [-F filename] [--file filename] [name]


       hostname [-v] [-h] [--help] [-V] [--version]


       dnsdomainname [-v]
       nisdomainname [-v]
       ypdomainname [-v]


DESCRIPTION
       Hostname is the program that is used to either set or display the
       current host, domain or node name of the system.  These names are used
       by many of the networking programs to identify the machine. The domain
       name is also used by NIS/YP.


   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, nisdomainname, ypdomainname will print the name of the
       system as returned by the getdomainname(2) function. This is also known
       as the YP/NIS domain name of the system.


       dnsdomainname will print the domain part of the FQDN (Fully Qualified
       Domain Name). The complete FQDN of the system is returned with hostname
       --fqdn.


       The function gethostname(2) is used to get the hostname.  When the
       hostname -a, -d, -f or -i is called will gethostbyname(3) be called.
       The difference in gethostname(2) and gethostbyname(3) is that
       gethostbyname(3) is network aware, so it consults /etc/nsswitch.conf
       and /etc/host.conf to decide whether to read information in
       /etc/sysconfig/network or /etc/hosts

       To add another dimension to this, the hostname is also set when the
       network interface is brought up.


   SET NAME
       When called with one argument or with the --file option, the commands
       set the host name, the NIS/YP domain name or the node name.


       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/rc.d/rc.inet1 or /etc/init.d/boot (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 gethostbyname(2) 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).

       -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.

       -F, --file filename
              Read the host name from the specified file. Comments (lines
              starting with a `#') are ignored.

       -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.

       -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.

       -h, --help
              Print a usage message and exit.

       -i, --ip-address
              Display the IP address(es) of the host. 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, --version
              Print version information on standard output and exit
              successfully.

       -v, --verbose
              Be verbose and tell what's going on.

       -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.

FILES
       /etc/hosts /etc/sysconfig/network

NOTE
       Note that hostname doesn't change anything permanently. After reboot
       original names from /etc/hosts are used again.

AUTHOR
       Peter Tobias, <tobias@et-inf.fho-emden.de>
       Bernd Eckenfels, <net-tools@lina.inka.de> (NIS and manpage).
       Steve Whitehouse, <SteveW@ACM.org> (DECnet support and manpage).





net-tools                         28 Jan 1996                      HOSTNAME(1)