RE: Can't telnet port 25 from server but can from other client

From: Julie Turner (JulieTurner_at_discussions.microsoft.com)
Date: 12/16/04 

Date: Thu, 16 Dec 2004 13:45:04 -0800

All outgoing email is blocked. Neither smarthost or DNS work (i've tried
both) but currently the configuration is using smarthost. I've tried 3
different smarthost servers. To eliminate DNS from the equation I'm using
the IP address of the smarthost and have verified they are responding to ping
tests before trying them. I think if you boil the problem down a little
deeper the problem is that I can't telnet on port 25 from the server to any
SMTP server even one in the same network. If I turn SMTP services on on a
client machine in the network I can't get to it etiher. But that client
machine can telnet outside the network to a smtp server on port 25 which
means my ISP isn't blocking port 25. It really seems like there is some sort
of firewall or something that's blocking port 25 traffic out of the server,
but I didn't turn the firewall on and there doesn't seem to be any way to
tell if it's running "accidentily".

"Michael Patrick" wrote:

> Okay, restarted.....still nada....
> Is it all outgoing e-mail that is getting stuck? Or just to a particular
> domain?
> And you didnt say if you are using a smarthost or dns to route e-mail...
>
> "Julie Turner" wrote:
>
> > Unfortunately starting and stopping the service did not do anything, although
> > I was fairly sure it wouldn't becuase I've restarted the server several times
> > today, and ran the internet and email connection wizard about 6 different
> > times, hoping that something just want's "taking".
> >
> > As I said in my other email I know the ISP isn't blocking traffic on port 25
> > for two reasons. The first, I called them and they said they don't. And the
> > second, becuase if I go to another machine on the local network and try
> > telnet smtp.mainesource.com 25 it connects. If I try to do the same thing
> > from the server, it fails to connect, however, I can't ping
> > smtp.mainesource.com and it responds so I'm fairly sure there is no DNS
> > problem.
> >
> > The real pain here is that it was working at one point and isn't now for no
> > apparent reason. There is a router and a DSL modem and they both have
> > firewalls however, it's my understanding that firewalls such as these only
> > block incomming traffic so I am not sure why I would want to open up port 25
> > unless I'm just missing something there.
> >
> > "Michael Patrick" wrote:
> >
> > > Just for the heck of it......go to System Manager (exchange), under admin
> > > groups, first admin, server, protocols, and then SMTP you have your virtual
> > > server..... try to stop and restart.....
> > >
> > > If that doesnt work, we may want to check your settings there......or do you
> > > have a router that might not be configured properly?
> > >
> > > Since you said it was working fine, and if restarting the SMTP server does
> > > not help....call your isp and see if they changed anything recently....they
> > > may have blocked your port 25 there..... Which this may be the case....
> > >
> > > Go to your SMTP Virtual server properties, delivery tab and advanced button
> > > what is listed in smarthost?
> > >
> > > "Michael Patrick" wrote:
> > >
> > > > Running ISA at all?
> > > >
> > > > "Julie Turner" wrote:
> > > >
> > > > > Hopefully someone has some ideas...
> > > > >
> > > > > For about 3 weeks email has been happily coming in on the pop3 connector and
> > > > > going out via forwarding to a smart host. Somehow something got changed and
> > > > > all the sudden email is stuck in the SmallBusiness SMTP connector queue. I
> > > > > cannot telnet to an external smtp server on port 25 from the SBS2003 server.
> > > > > However, I can do so from another computer on the internal network which
> > > > > disproves my original assumption that the ISP was blocking port 25.
> > > > >
> > > > > The Firewall on the server is turned off... or is the the best of my ability
> > > > > to ascertain. However, it's been suggested to me that the server is blocking
> > > > > outgoing traffic on that port. I've checked the TCP/IP filtering on the
> > > > > network connection and none are set up...
> > > > >
> > > > > So at this point i'm at a loss. Anyone have any ideas?