On the computer

All distributions

TODO: develop procedure for renaming the volume group and document here (when / is on LVM as ours normally are, this may require rebuilding the initial RAM disk, re-configuring the boot manager, editing fstab ...).  Maybe useful links: https://we.riseup.net/debian/renaming-a-lvm-root-volume-group, https://bugzilla.redhat.com/show_bug.cgi?id=230190#c17 (RedHat),

TODO: is any postfix re-configuration required?

Debian

Reference: Debian WIKI page on changing hostname.

Slackware

As root either run netconfig (full prompted re-configuration requiring IP addresses and domain name) or do it the manual way by editing:

1. /etc/hosts
2. /etc/HOSTNAME
3. /etc/NetworkManager/NetworkManager.conf (if it exists)
4. /etc/rc.d/inet1.conf (if supplying hostname to DHCP server)

then run /bin/hostname $(cat /etc/HOSTNAME | cut -f1 -d .)

If running or using any of avahi, CUPS, ejabberd, Exim, /etc/motd, OpenSSH server, ssmtp or sysklogd then read the  Debian WIKI page on changing hostname

Ubuntu

• edit /etc/hostname
• edit /etc/hosts
• service hostname restart

Not tested (may all be done by the commands above): if running or using any of avahi, CUPS, ejabberd, Exim, /etc/motd, OpenSSH server, ssmtp or sysklogd then read the  Debian WIKI page on changing hostname.

Changes required on other computers

DNS servers

On DNS servers which have record(s) for the old name, change both the forward and reverse data files.

When the hostname of a system on the Blue Light LANs (192.168.10.0 and 192.168.28.0) is changed, the DNS service on backupserver will need re-configuring as documented in DNS server (bind) administration.

/etc/hosts files

On computers with an /etc/hosts file which has record(s) for the old name, change the line.