ssh_config's Hosts directive

[Sean Aaron Lisse]

> I'm trying to arrange the SSH client here to default to allowing
> X forwarding etc. to local machines (within the .dur.ac.uk domain)
> without forwarding X to off-site machines.

Note that using names instead of ip addresses leaves you vulnerable to
some nasty DNS attacks (of course, IP authentication in the first place is
less than perfect).  They're not too likely to give you problems so long
as you also use (password/crypto/whatever) authentication such as ssh uses
normally, but they're something to watch out for.

 -Sean Lisse