I just played around with this (on XP SP3 only) and found browsers handle the words differently.
Add to that OS differences and this might take some testing.
You can solve the dns issue by making an entry in the static dns for "logoff", but that is only part of the problem.
OS:
You have to make sure each OS resolves "logoff" correctly.
Windows appends the domain suffix to words with no "." so "logoff" becomes "logoff.domain" This is so you can browse local machines presumably. You will get different results with an nslookup of "logoff" vs "logoff."
Other OS's may have their own quirks. So I set a domain in the dhcp server. Even a dummy domain can work.
Browsers:
Chrome seems to send anything it doesn't understand to google search. After all, they know everything.
So no matter what you do with dns, it doesn't care and sends it to google search. At least my chrome, and mine is vanilla.
With the domain set, chrome correctly looks up the words with domain appended if you type "
http://logoff". Without http:// it doesn't work for me.
Firefox will cooperate (I have no plugins like google toolbar, etc) as long as you have a domain set.
I found FF will take "logoff" and treat it as if you want the host named "logoff" which doesn't exist. Page cannot be displayed.
It doesn't default to a search.
Adding a domain causes it to do a dns lookup for logoff.domain.
Then you can proxy this to the correct logoff url.
I did not try IE. I try not to use IE.
OpenDNS has shortcuts, so if you leave out the static entry, it will go to OpenDNS and try to match "logoff".
It's easy then to make a shortcut "logoff" => "
http://blah-blah"
I hope what I've already tried and discovered helps