Computer host name

[Steve]

---- Rick Stevens <ricks at nerd.com> wrote: 
> James Allsopp wrote:
> > Hi,
> > I've deactivated NetworkManager as it was interfering with my wireless
> > networking, but since then my computer has been renamed to
> > <ip-address>-bethere.co.uk, instead of localhost.localdomain. I've
> > looked at /etc/hosts
> > /etc/sysconfig/network
> > and these are all set up as localhost.localdomain and the network card
> > facing the internet is set up statically.
> > 
> > Anyone have any ideas how to stop this happening?
> 
> If you are running a DHCP client (and it looks like you are), the DHCP
> server you're using gave your machine a host name.  That's pretty
> normal.

I don't think that this is true. At least not if you're running dhcp-4.0.0 as I am on my F9 system.
$ rpm -qa | grep dhclient
dhclient-4.0.0-22.fc9.x86_64

I had thought the same thing but I recently spent some time sifting through the code to try to find where the host name is set. What I found is that it's not set by dhclient at all. It is set in the script 
/etc/sysconfig/network-scripts/ifup-post by the ipcalc command which is passed the IP address that the DHCP server gives your machine. Essentially this is a DNS lookup.

If you know otherwise or if this is not always true, I'd be interested to hear about it.

> My guess is that your ISP is "bethere.co.uk", therefore they gave you
> a hostname that reflects the IP address they gave you.  That's good,
> generally, because that means they're probably maintaining a reverse DNS
> entry for your IP address that points at you.
> 
> You can ignore the host name the DHCP server gives you by editing the
> DHCP client config on your machine and adding
> 
> 	supercede host-name localhost.localdomain;
> 
> to the lease clause.  See "man dhclient.conf" and "man dhcp-options".

You can also put

send host-name "my_host_name";

in the dhclient.conf file or add

DHCP_HOSTNAME="my_host_name"

to /etc/sysconfig/network

Steve