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HacDC's MX record broken, can't send mail to lists
Dangit. I'm sure someone will find this here, as I'm unable to send to any of the mailing lists. Here's a convo between me and my admin:
12:39 <myself> hey, I keep getting this whenever I try to send to hacdc:
12:39 <myself> firstname.lastname@example.org
12:39 <myself> all relevant MX records point to non-existent hosts or (invalidly) to IP addresses
12:40 <myself> but there's plenty of traffic on the list, others obviously have no problems
12:40 <myself> I mentioned it to one of them through his personal email, and didn't hear back. Is this something you can look into?
13:03 <paul> paul@ptimmins-d:~$ host hacdc.org
13:03 <paul> hacdc.org has address 220.127.116.11
13:03 <paul> hacdc.org mail is handled by 0 18.104.22.168.
13:03 <paul> that's invalid
13:03 <paul> cant' fix
13:04 <paul> mx records have to point to names per rfc
13:05 <myself> ahh, okay
13:05 <myself> thanks
13:05 <paul> that should be something like
13:05 <paul> MX 0 mail.hacdc.org.
13:05 <paul> with mail.hacdc.org. IN A 22.214.171.124
13:06 <myself> and everyone else's MTAs just silently accept the misconfiguration and do the right thing anyway
13:07 <paul> where by "the right thing" you mean "do what I mean not what I say"
13:07 <paul> yes
13:08 <paul> they added extra code paths to compensate for the dns calls not returning shit they should
13:08 <paul> when you pull an A record, the IPs get returned in binary
13:08 <paul> when you pull an MX record, it spells out the data in ascii because it's supposed to be another name
13:09 <paul> which you can then do a gethostbyname() on and get an ip
13:10 <paul> so other MTAs have an entire codepath where they try to parse an ASCII string of an IP address to stuff it into a connect()
13:10 <paul> which is as bad of an idea as it sounds, securitywise
Fixed - thanks for the heads up!