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cant telnet to my gwy via port 25

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cant telnet to my gwy via port 25 - 1.Jul.2008 11:31:38 PM

ceez

Posts: 42
Joined: 16.Dec.2005
Status: offline

hey guys, we're having a horrible problem with our front end and backend.
both running server 2003 and exchange 2003 with all their corresponding service packs.
we can receive internal emails BUT NOT EXTERNAL
we were talking to our barracuda appliance spam filter tech support and they noticed that they couldnt telnet from their appliance to our gateway
he said that the problem we're having is because our gwy is not accepting connections on port 25, therefore the appliance cant communicate with the gateway and the gateway cannot communicate to the backend and deliver the messages.
we also have outgoing messages stuck on the backend, supposedly cant communicate with the gateway via port 25
so in my winxp sp3 workstation i go to cmd prompt and type
telnet mail.mydomain.com 25 [enter]
It clears the screen and I just get an underscore "_"
as soon as i press any key i go back to my command prompt C:>

I've tried searching the web but I have not found a good troubleshooting process.
our setup is very simple, front end and backend no smtp connectors, pretty much straight "outta the box" setup.
thank you and I really appreciate your assistance.
Cesar

****UPDATE****
I can telnet to localhost on my backend BUT NOT on the front end.
I can telnet FROM the backend to the frontend
I CANNOT telnet from frontend to backend

Something is wrong with port 25?!?!?

how can I fix this!

OMG I am gonig to so jump out of a window?!!?! :(

< Message edited by ceez -- 2.Jul.2008 12:17:06 AM >

Post #: 1

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RE: cant telnet to my gwy via port 25 - 2.Jul.2008 12:26:08 AM

uemurad

Posts: 5198
Joined: 7.Jan.2004
From: California, USA
Status: offline

The first thing I would check is whether your SMTP service is running on your Exchange server (Simple Mail Transport Protocol). If it is running, try restarting the service. If that doesn't work, try executing IISreset. If that doesn't work, dismount all the stores and reboot the server.

Also consider any recent changes. Consider any devices between the Barracuda and your Exchange server. Any firewalls or routers? Did you change the port number on the SMTP Virtual Server?

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to ceez)

Post #: 2

RE: cant telnet to my gwy via port 25 - 2.Jul.2008 9:23:26 AM

ceez

Posts: 42
Joined: 16.Dec.2005
Status: offline

C:\>iisreset /status
Status for World Wide Web Publishing Service ( W3SVC ) : Running
Status for Simple Mail Transfer Protocol (SMTP) ( SMTPSVC ) : Running
Status for Microsoft Exchange Routing Engine ( RESvc ) : Running
Status for Microsoft Exchange POP3 ( POP3Svc ) : Running
Status for Network News Transfer Protocol (NNTP) ( NntpSvc ) : Stopped
Status for Microsoft Exchange IMAP4 ( IMAP4Svc ) : Running
Status for HTTP SSL ( HTTPFilter ) : Running
C:\>iisreset /restart
Attempting stop...
Internet services successfully stopped
Attempting start...
Internet services successfully restarted
C:\>

SMTP seems like it's running and the reset did not work, is there another cmd line swith for it?

We've restarted this server already as well as the stores via services but no luck.

(in reply to uemurad)

Post #: 3

RE: cant telnet to my gwy via port 25 - 2.Jul.2008 10:00:57 AM

uemurad

Posts: 5198
Joined: 7.Jan.2004
From: California, USA
Status: offline

The simplest way to check is to telnet to port 25 on the Exchange server itself. Do you get the Microsoft ESMTP banner? If so, then inbound port 25 should be fine. In that case, I'd go back to the question about the devices capable of port blocking between your gateway and your Exchange server.

To stop and start a single service, you can use the command lines:
NET STOP <servicename>
NET START <servicename>

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to ceez)

Post #: 4

RE: cant telnet to my gwy via port 25 - 8.Jul.2008 3:42:50 PM

ceez

Posts: 42
Joined: 16.Dec.2005
Status: offline

so we got it resolved last week, but wanted to update in case someone has a similar issue.

a setting was changed on the smtp protocol of our front end server
smtp properties-access tab-connection.
the radio button selected was "only the list below" and the list was empty.

Once I added the IP of our backend server the emails started pouring like water.

I also added the static IP address of my workstation for troubleshooting purposes in the future.

(in reply to uemurad)

Post #: 5

RE: cant telnet to my gwy via port 25 - 8.Jul.2008 3:48:03 PM

uemurad

Posts: 5198
Joined: 7.Jan.2004
From: California, USA
Status: offline

Thanks for posting your solution. It probably goes without saying, but you should find out who made the change and why. What was the expected effect, and why wasn't the change undone as soon as the problem appeared?

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to ceez)

Post #: 6