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Clients on same subnet as me can't get email from me.

Posted on 2011-03-18
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Last Modified: 2012-06-27
I'm a noob, so forgive any errors in terminology.

I've noticed a pattern. It seems like our A records are all on the same subnet of 64.129.12.xx. Please note: we are not in the same company -- we just send emails to each other. The only coincidence is our IP addresses. This problem only happens with clients on the same IP address pattern.

I can send email to them. They can't send to me. My mail server log says: Winsock Error 10054 Connection was reset by the other side!

My domain name is rnsha.com. Does nslookup provide a clue?

Do you need more info?

Please help!
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Question by:NVIT
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by:BCipollone
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rjpilcher earned 400 total points
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This is probably related to a misconfigured firewall/router on your side, his side, or your provider.  I'd check those three avenues out first.

Also, try to do a telnet to his mail server from yours and do a command line send mail test:

http://support.microsoft.com/kb/153119
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by:NVIT
ID: 35169898
Hey guys. Thanks for your responses. I appreciate it.

We have a sonicwall soho.

Can you clue me in or do you know what settings I should check?
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by:rjpilcher
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I'd start off with the telnet test.

Next I'd look at the mask settings and make sure you don't have any deny statements that could be affecting this.

I've seen issues with the provider's routing table cause this, even in the same datacenter.

Also, just to be thorough, make sure either of you aren't on a RBL:

http://mxtoolbox.com/blacklists.aspx
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by:NVIT
ID: 35185779
rjpilcher,

Here's what I've done so far...

Here's my email server log snippet when the client tries to send to us:
Fri 2011-03-18 09:47:59: Accepting SMTP connection from [64.129.12.191:26318] to [0.0.0.0:25]
Fri 2011-03-18 09:47:59: Performing PTR lookup (191.12.129.64.IN-ADDR.ARPA)
Fri 2011-03-18 09:48:00: *  D=191.12.129.64.IN-ADDR.ARPA TTL=(1440) PTR=[email.castle-cooke.com]
Fri 2011-03-18 09:48:00: *  Gathering A records...
Fri 2011-03-18 09:48:00: *  D=email.castle-cooke.com TTL=(1440) A=[64.129.12.191]
Fri 2011-03-18 09:48:00: ---- End PTR results
Fri 2011-03-18 09:48:00: --> 220-rnsha.com ESMTP MDaemon 11.0.1; Fri, 18 Mar 2011 09:48:00 -1000
Fri 2011-03-18 09:48:00: --> 220 All transactions and IP addresses are logged.
Fri 2011-03-18 09:48:00: *  Winsock Error 10054 Connection was reset by the other side!

On our mail server, I use nslookup:
> set type=mx
> castle-cooke.com
Non-authoritative answer: castle-cooke.com        MX preference = 10, mail exchanger = mail.castle-cooke.com

Question:
Why does nslookup return a different name, i.e. mail.castle-cooke.com vs. my mail server log, i.e. email.castle-cooke.com?

For the blacklist at mxtoolbox.com:
64.129.12.191 (email.castle-cooke.com) is good. Do timeouts count?
64.129.12.85 (rnsha.com - my company) is good.

For mask settings:
I checked my SOHO for any IP patterns w/ 64.129.12.*, but couldn't find any.

What else should I check?
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by:NVIT
ID: 35185845
I forgot to add to my last post...

Telnet:
I telnetted locally from the mail server, and from a workstation on the same subnet.
Both results in:

telnet email.castle-cooke.com 25
takes awhile to respond. Then says: Connecting To email.castle-cooke.com...Could not open connection to the host, on port 25: Connect failed

telnet mail.castle-cooke.com 25
responds quickly. Then says: Connecting To email.castle-cooke.com...Could not open connection to the host, on port 25: Connect failed
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by:NVIT
ID: 35185851
*** Off topic
Is there a way to edit a post I make?
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