I am supporting 28 Palm Treo 755s. They are set up with a Versamil account
that sends email through our internal mail server so it will appear to come
from our office. This has not been much of a problem in the past. At first I
had to make some relay exceptions in the GWIA, but once they were made
everything worked fine.

Recently however, our provider seems to be acquiring new IP addresses every
day. Sometimes the phones will get a new IP address 2 or 3 times each day
and it is always one that I have not made an exception for. I have added
some pretty broad ranges, (i.e. ###.###.*.* ) but it is getting out of hand.

Is there another solution to this, preferably one that would continue to
make the email appear to come from our firm?