newnews command from microsoft exchange 5.5 server

[Laszlo Vecsey]

I have microsoft exchange 5.5 set to do a 'newnews' request every hour,
and it gives me the following error message:

--
An error response was received to a newnews command from server Newsfeed
news.hostname.com (HONCHO). The response code was 502.  The pull feed
connection has been terminated. 
--

On the server side (yesterdays inn snapshot), I see the newnews command
listed along with a bunch of groups in the form of
"groupname.*,groupname.*" etc, and a few failures for not being able to
set the NNTP-Posting-Host, X-Trace, and X-Complaints-To headers.

The exchange server has all the service packs, one of which dealing with a
512byte limit on the newnews command length, but other than that nothing
else mentioned in the change logs..

Is there something I need to configure on the inn server?