When the hostname in /etc/sysconfig/network gets set a name in my
local network ("volker", ip 192.168.1.1), sendmail hangs when you do
"/etc/rc.d/init.d/sendmail start", making the whole system unbootable.
When I set the name to "localhost", it works. The network does not have
a subnet name.
The hostname should be a FQDN and you also need it resolvable by the resolver
(usually you need it defined in /etc/hosts or you have to have /etc/resolv.conf