Rename a computer

This page explains how to change a system's hostname (i.e. rename a computer/server)

Executive summary: hostname(1) isn't enough.

Contents

Rename a computer

Core networking

Update /etc/hostname
Update /etc/hosts, so local address(es) resolves with the new system name.
Reload the network configuration. You have two options
- Reload configuration files
  This will temporarily disconnect your system from the network (ssh usually resists short disconnection)
```
invoke-rc.d hostname.sh start
invoke-rc.d networking force-reload
invoke-rc.d network-manager force-reload
```
  ToDo: is it useful to reload network-manager?
- or the lazy way: Restart the system.

Application specific

avahi

Avahi is used to publish (announce) local services. If you tweaked /etc/avahi/* you should run:

```
invoke-rc.d avahi-daemon force-reload
```

CUPS

Adjust /etc/printcap . You need to restart the service.

ejabberd

See the How to Change Domain Name? FAQ entry in the ejabberd book.

Temporarily adjusting the value of ERLANG_NODE in /etc/default/ejabberd to include the old hostname, can be used to re-establish service functionality, for performing a database backup.

Exim

Adjust /etc/exim4/update-exim4.conf.conf (hostname=). You need to restart the service.

Mailname

Adjust /etc/mailname. You don't need to restart the service.

Message Of The Day

Adjust /etc/motd. You don't need to restart a service.

OpenSSH server

Adjust /etc/ssh/ssh_host_rsa_key.pub and /etc/ssh/ssh_host_dsa_key.pub (root@hostname at the end). You need to restart the service.

ssmtp

Ssmtp is a light weight, send-only SMTP server.

Adjust /etc/ssmtp/ssmtp.conf (hostname=, etc.). You don't need to restart the service.

Idea of script to help you on

Intrusive script

Please understand that this script is dangerous. You should check if all the files listed by grep -rl "$ancien" /etc must really be modified before launching this script

   1 #!/bin/bash
   2 #
   3 usage() {
   4    echo "usage : $0 nouveau_nom_hote"
   5    exit 1
   6 }
   7 
   8 [ -z $1 ] && usage
   9 
  10 ancien=`hostname`
  11 nouveau=$1
  12 
  13 grep $ancien /etc/ -rl 2>/dev/null | while read file
  14    do
  15       sed s:$ancien:$nouveau:g $file > ${file}.tmp
  16       mv ${file}.tmp $file
  17    done

Take care you'd better do a grep before...

Not-so intrusive script

#!/bin/bash
# 
usage() {
   echo "usage : $0 nouveau_nom_hote"
   exit 1
}

[ -z $1 ] && usage

ancien=`hostname`
nouveau=$1

for file in \
   /etc/exim4/update-exim4.conf.conf \
   /etc/printcap \
   /etc/hostname \
   /etc/hosts \
   /etc/ssh/ssh_host_rsa_key.pub \
   /etc/ssh/ssh_host_dsa_key.pub \
   /etc/motd \
   /etc/ssmtp/ssmtp.conf
do
   [ -f $file ] && sed -i.old -e "s:$ancien:$nouveau:g" $file
done