Exchange not sending outside mail

fjmeat

Diamond Member
Jan 13, 2010
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I recently installed exchange 2003 on dell poweredge running windows server 2003. It can send internal emails within my domain with no issues. It can receive any internal or outside emails. However, it won't send to any other outside/internet email accounts. Any ideas as to why this is happening?
 

AKA

Golden Member
Oct 10, 1999
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It is possible your isp is blocking the smtp port 25.
 
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fjmeat

Diamond Member
Jan 13, 2010
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Can you help point me toward the instruction of a Smart Host using the ISP's mail server as the forwarder?
 

IndyColtsFan

Lifer
Sep 22, 2007
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Can you help point me toward the instruction of a Smart Host using the ISP's mail server as the forwarder?

Just Google Smart Host and Exchange 2003. This article might help. I haven't messed with Exchange 2003 in a number of years so I don't remember the steps off the top of my head, but when I ran it at home, I had to do a Smart Host not to avoid a blocked SMTP port, but to get around email blacklists that typically contain the dynamic IP address ranges of large ISPs and were causing emails from my server to be rejected by companies who subscribed to these lists.
 

fjmeat

Diamond Member
Jan 13, 2010
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thanks for the help; step 6 on the article above says:

"Select Forward All Mail Through This Connector To The Following Smart Hosts, and enter the IP address of the other site's mail server, enclosed in brackets (e.g., [172.25.3.110])."

My ISP at home AT&T

What do I need to enter as "the IP address of the other site's mail server?"
 

IndyColtsFan

Lifer
Sep 22, 2007
33,655
688
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thanks for the help; step 6 on the article above says:

"Select Forward All Mail Through This Connector To The Following Smart Hosts, and enter the IP address of the other site's mail server, enclosed in brackets (e.g., [172.25.3.110])."

My ISP at home AT&T

What do I need to enter as "the IP address of the other site's mail server?"

If you have an AT&T mail account and use something like Outlook to use it, look at your Outlook config. The SMTP server in that config is the one you specify in the Smart Host config.
 

fjmeat

Diamond Member
Jan 13, 2010
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smtp.att.yahoo.com

Does that sound right? I thought it was asking for actual numbers, but i'll give it a shot.
 

RebateMonger

Elite Member
Dec 24, 2005
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This just started happening this afternoon, Exchange was setup Friday evening, was working fine up until this afternoon, it just stopped sending outside emails. very strange.
Open a Command Prompt on the Server and attempt to Telnet to TCP Port 25 on a couple of other mail servers. You'll have to look up the MX records for a few mail servers:

"Telnet mx3.hotmail.com 25"
"Telnet mail3.foxnews.com 25"

You should see a response from their mail servers. Both of the above servers are responding to my requests tonight. If you can't connect, then there's probably an outgoing firewall in place. Do you have a Home or Business Internet account? If Home, then maybe your ISP is now blocking outgoing TCP Port 25 connections. Cox blocked outbound requests to non-Cox mail servers years ago (on Cox Home accounts).

If outgoing TCP Port 25 isn't being blocked, then it's time to look at the Exchange Queue and the Message Tracking tool in ESM.
 
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IndyColtsFan

Lifer
Sep 22, 2007
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You need to ask ATT or look up which of their mail servers is configured as a smarthost. It's likely not one of the servers used for consumer email. Cox has a separate smarthost server and, apparently, so does ATT:

http://text.broadbandreports.com/forum/r19926669-Using-ATT-as-smarthost-with-Exchange-2k3

I think something else is at play here. I briefly had to use AT&T DSL about a year ago, and all I did was use the consumer email servers as Smart Hosts and it worked like a charm. I would think that even if they had blocked port 25, it would be on an edge firewall/router and that he should be able to at least forward email to their internal email server for forwarding.

There is something wrong with Exchange or perhaps they did a network scan, saw open ports indicative of an email server, and are blocking his email server by IP.