I just put ubuntu on my office computer, got it to connect o.k. to the
internet, BUT it doesn't recognize my outgoing or incoming email servers
and for some reason, the firefox won't connect. although i can see on
the ext. modem (and hear on the phone line) that it IS connected.
any ideas ???

Matt and der.hans have good suggestions. I would add that it does seem a bit odd to be using dial-up from an office computer (though not unheard of). But based on other experiences, I can say that Linux in general does not always handle having two separate paths to the internet very well. Case in point being a system having both a wired and a wireless connection even via the same router. you might want to try ifconfig to see if the system believes it has two working interfaces to the net.