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Currently, the e-mail servers trying to deliver mail from stackexchange to my address appear to sit behind 69.59.196.221:

Dec 18 21:33:56 avalon postfix/smtpd[1132]: NOQUEUE: reject: RCPT from unknown[69.59.196.221]: 450 4.7.1 Client host rejected: cannot find your hostname, [69.59.196.221]; from=<do-not-reply@stackexchange.com> to=<myemailaddress@example.org> proto=ESMTP helo=<mx-out.stackexchange.com>

As you can see, my mail server rejects this e-mail, since it cannot find the IP address 69.59.196.221 in the records for mx-out.stackexchange.com, where it should be in every sane set-up (don’t claim to be A when A claims not to know you).

The actual records as available in the DNS at the moment:

$ dig -x 69.59.196.221 PTR +short
peak-colo-196-221.peak.org.
$ dig mx-out.stackexchange.com +short
72.51.63.225
64.34.119.225

Is it possible to fix this such that 69.59.196.221 is listed as one of the hostnames for mx-out.stackexchange.com?

share|improve this question
2  
I opened this with the intention of VtC as "Off topic" :P. – Matt Dec 18 '12 at 22:09
1  
Well there should only be a few mail servers for which MSO is on-topic, so I thought I could save the ‘SE’ in front of ‘e-mail servers’ :-) – Claudius Dec 18 '12 at 22:12
5  
I'm on it, standby. – Peter Grace Dec 18 '12 at 22:14
1  
@Claudius MSO receives multiple questions every day that ought to be posted on SO or SF or some other site, but weren't due to their OPs being brand-new, utterly confused or question-banned on the appropriate site. – Pops Dec 18 '12 at 22:20
up vote 9 down vote accepted

This is an oversight on our part, we did not add it to the DNS record when we failed over to Oregon during SUPERSTORM SANDY. I have pushed the proper IPs into the A record and it should sync over the next hour or so.

for ((i=1;i<=4;i++)); do host mx-out.stackexchange.com ns$i.serverfault.com; done
Using domain server:
Name: ns1.serverfault.com
Address: 64.34.119.33#53
Aliases:

mx-out.stackexchange.com has address 64.34.119.225
mx-out.stackexchange.com has address 72.51.63.225
mx-out.stackexchange.com has address 69.59.196.221
mx-out.stackexchange.com has address 69.59.196.222
Using domain server:
Name: ns2.serverfault.com
Address: 64.34.119.34#53
Aliases:

mx-out.stackexchange.com has address 64.34.119.225
mx-out.stackexchange.com has address 72.51.63.225
mx-out.stackexchange.com has address 69.59.196.221
mx-out.stackexchange.com has address 69.59.196.222
Using domain server:
Name: ns3.serverfault.com
Address: 69.59.196.217#53
Aliases:

mx-out.stackexchange.com has address 64.34.119.225
mx-out.stackexchange.com has address 69.59.196.221
mx-out.stackexchange.com has address 69.59.196.222
mx-out.stackexchange.com has address 72.51.63.225
Using domain server:
Name: ns4.serverfault.com
Address: 69.59.196.122#53
Aliases:

mx-out.stackexchange.com has address 69.59.196.221
mx-out.stackexchange.com has address 69.59.196.222
mx-out.stackexchange.com has address 64.34.119.225
mx-out.stackexchange.com has address 72.51.63.225
share|improve this answer
1  
Looks good, thank you very much for the quick response. If I remember correctly, it would probably also be a good idea if the PTR records for these IPs (currently peak-colo-196-221.peak.org. for 69.59.196.221 and correspondingly for .222) would again resolve to/include said IPs. This is done for 72.51.63.225 and 64.34.119.225 already (these resolve to mx-out.stackexchange.com) – Claudius Dec 18 '12 at 22:27
    
This is something that will have to wait until we get more IP addresses at PEAK. .221 and .222 are our nat overload addresses and I don't want to explicitly give them a PTR. – Peter Grace Dec 19 '12 at 1:30
1  
This is not fixed. Feb 7 16:33:11 eclipse postfix/smtpd[22889]: connect from unknown[69.59.196.222] Feb 7 16:33:12 eclipse postfix/smtpd[22889]: NOQUEUE: reject: RCPT from unknown[69.59.196.222]: 450 4.7.1 Client host rejected: cannot find your hostname, [69.59.196.222]; from=<do-not-reply@stackoverflow.com> to=<me@mydomain.com> proto=ESMTP helo=<mx-out.stackexchange.com> Feb 7 16:33:12 eclipse postfix/smtpd[22889]: disconnect from unknown[69.59.196.222] – Milos Ivanovic Feb 7 '13 at 3:54
    
To be clear, what Milos is complaining about is the missing PTR records, not the A records (these are good). And if that's the reason I haven't received the newsletter recently, then… please do get those extra IPs asap. – Félix Saparelli Feb 7 '13 at 4:36
    
We'll be moving back to New York very soon, which should resolve this issue for those with PTR-checking mailservers. – Peter Grace Feb 7 '13 at 8:23

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