Comment 41 for bug 8980

I just did test installs of 8.04.2 and 9.04 alpha 3, using the i386 alternate ISO in each case. I answered the question about the hostname by supplying the FQDN in each case. Immediately on completion of each install, I checked the various files.

For the jaunty alpha, the domain was correctly split, the unqualified hostname was placed in /etc/hostname, and the entry for 127.0.1.1 in /etc/hosts had the FQDN then the unqualified host name. However, there is no domain entry in /etc/resolv.conf

For the 8.04.2 install, the FQDN went into /etc/hostname, and /etc/hosts had
127.0.0.1 localhost
127.0.1.1 host.dom.ain.dom.ain host.dom.ain

- ie the domain was duplicated.

I then checked the General tab of network-admin on the newly-installed 8.04.2, and found the FQDN in the host field, while the domain field was blank. An attempt to change the details using network-admin updated /etc/hostname and /etc/resolv.conf, but did not update /etc/hosts (although the timestamp for all 3 files was updated). The update to /etc/resolv.conf was to append a domain line. (The domain line will disappear next time Network Manager over-writes /etc/resolv.conf with DNS server details learnt from DHCP, but that is a separate bug.)
Because there is no line in /etc/hosts with an entry matching the value in /etc/hostname, hostname succeeds, but 'hostname -f' fails with 'hostname: Unknown host'.