Al
Fri Sep 10 08:25:31 CDT 2004
When you say 53 what EXACTLY do you mean?
Sending mail in Win2Kx/Exchange2Kx requires that you have the ability to
converse TO TCP 25 on the remote host. You also need to be able to find the
remote host which by default requires UDP 53 to a DNS host. You should also
allow TCP 53 to the remote host.
That said, that's for outgoing mail only. All other traffic needed is much
different when talking to the Active Directory.
If NSLOOKUP doesn't work, DNS won't either. Remember that all traffic can
originate from any random port but will only be destined for the well known
ports described.
-Al
"Frank" <anonymous@discussions.microsoft.com> wrote in message
news:087d01c49728$ecd0cf10$a401280a@phx.gbl...
>I have a mail server with two NICs. One is internal, one
> is external. Routing is not enabled. If I set TCP/IP
> filtering on the external adapter to only allow traffic to
> 25 and 53, I can't send but I can receive OK.
>
> With TCP/IP filtering on, I can receive but not send, all
> messages sit in the Outbound queue with the tag <network
> error...' - a DNS sounding problem. NSLOOKUP doesn't
> work. So, are my DNS requests not going to 53? Is that
> what this is telling me?
>
> With no filter, everything is fine.
>
> I spoke to my ISP, who waffled a lot and didn't really
> tell me anything, I don't think they wanted to admit not
> knowing the answer.
>