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

From: Julie Turner (JulieTurner_at_discussions.microsoft.com)
Date: 12/17/04 

Date: Fri, 17 Dec 2004 07:23:03 -0800

First, thank you all for your ideas... here's what I found from your
suggestions

Ok. CEICW tells me that it's not configuring the firewall becuase I only
have one NIC. So that's why I don't think the firewall is turned on. The
network configuration in the CEICW has always failed from day one, but the
email was working then so I have always just fixed the settings in the
network configuration myself. Otherwise the other three complete fine. What
the CEICW doesn't set right is the DNS.... for some reason it set's it to the
server's IP address.. I just mod it to point to the modem (which is pointed
out to 2 ext. DNS servers that the ISP manages.)

Anyway, here's the IPCONFIG /ALL
Windows IP Configuration

   Host Name . . . . . . . . . . . . : MS-SERVER
   Primary Dns Suffix . . . . . . . : MaineSource.local
   Node Type . . . . . . . . . . . . : Unknown
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : Yes
   DNS Suffix Search List. . . . . . : MaineSource.local

Ethernet adapter Server Local Area Connection:

   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : Intel(R) PRO/1000 CT Network Connection
   Physical Address. . . . . . . . . : 00-C0-9F-47-33-83
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 10.0.0.4
   Subnet Mask . . . . . . . . . . . : 255.0.0.0
   Default Gateway . . . . . . . . . : 10.0.0.2
   DNS Servers . . . . . . . . . . . : 10.0.0.2

There is nothing in the modem (which is acting as the router) to indicate
that it's blocking outgoing traffic... further, since another machine on the
internal network can telnet out to smtp.mainesource.com on port 25 I feel at
this point I've narrowed the problem down to the server specifically.
10.0.0.9 is also running the SMTP service and the server at 10.0.0.4 cannot
telnet to it either on port 25 but it can ping it.

To be honest I'm not 100% sure what ISA is and how to turn it on... if it is
on I didn't turn it on intentionally and I can't find any programatic
reference to it now to check anything. What's confusing here is that if that
was the problem then it got turned on sometime in the last week becuase this
whole thing was working about 2 weeks ago.

I currently do not have any A/V installed so that is not the problem... it
was my next step but of course, since I haven't gotten the email running I
haven't moved there yet.

My incomming mail from the pop3 connector is coming in fine... I just can't
send email back out again through the SMTP connector. But again, since I
can't telnet out of the server on port 25 I'm not expecting it to either.

I tried applying the hotfix... unfortunately that did nothing. I have now
also tried uninstalling and reinstalling the SMTP service. That also did
nothing.

"Julie Turner" wrote:

> 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?