Unable to deliver due to communications failure

[nhanley]

I am running Exchange 5.5 with Service Pack 4 on Windows NT 4.0 and all of a sudden I am getting an error message when sending to a particular domain.

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Your message did not reach some or all of the intended recipients.

Subject: test
Sent: 7/13/2004 9:11 AM

The following recipient(s) could not be reached:

'n_hanley@comcast.net' on 7/13/2004 9:11 AM
Unable to deliver the message due to a communications failure
The MTS-ID of the original message is: c=US;a= att;p=roofonline;l=DS9-040713141035Z-47080

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I thought it might be a DNS error but when I do the nslookup -type=mx comcast.net everything seems fine. Any help would be apppreciated.

 

[judykim88]

I do have sam problem as above but I could not solve problem.
Anybody can help us?

 

[judykim88]

I found what is problem.
My sever ip address is listed on the spam list.
You better check it out spam database lookup.

http://www.dnsstuff.com/

If you find it, remove your ip from spam list.

 

[nhanley]

I checked that a while ago and we are not listed on any spam databases unfortunately.

 

[judykim88]

I checked my e-mail server ip address but it's not on the list. I have firewall and all network go out through the firewall. So I check out my firewall ip address then I found we are on the list. If you have any firewall, try that.

 

[nhanley]

Thanks for the tip. I did check the firewall address and it was listed so I got it unlisted but I am still having the same problem.

 

[judykim88]

It takes a time to remove. It takes at least feww hour or 1 day.

 

[nhanley]

I checked the lists this morning and we are gone but we still cannot email to comcast.net.

 

[superjet]

I had the same problem and it turned out to be our new Firewall.
Have you made any firewall changes as of late?

 

[nhanley]

Yes, there was a couple of changes made to the firewall because we put in a spam firewall so I had to route the incoming email from the firewall to the spam firewall and then to the mail server. I did not think this would affect the outgoing mail but I will check it out though because I think this problem occured around that time.

 

[omni17]

http://faq.comcast.net/faq/answer.jsp?name=17705&cat=Email&subcategory=1

comcast started blocking ports a few weeks ago. there is the link to their official position on this topic.