easiest way to override foreign MX records for outgoing mail

I need to send mail to a site whose DNS zone seems to have lost its MX records sometime last week. Now the recipient domain has only an A record, pointing to a different box (not a mailserver). Per RFC 5321, my MTA sees there are no MX records, tries to send to the A record, and fails with a timeout.

I happen to know the mailservers that are supposed to be in the MX records, and email is my only way to contact these guys (their servers are 9000 miles away in Vanuatu, no phone number, and who knows how much a tech support call to Vanuatu would cost per minute anyway).

If it helps, the recipient domain is vunic.vu and the missing mailservers are mail.vanuatu.com.vu and mail2.vanuatu.com.vu.

My current idea is to set up nsd3 on my linode, create an authoritative zone for vunic.vu with the correct MX records, and add localhost to /etc/resolv.conf. Then, my box isn't set up to handle outgoing mail, so I would have to set that up somehow.

This strikes me as a fairly ugly solution, and email isn't my strong point, so am I missing any easier way to handle this? Right now I'm using Postfix for a simple incoming only setup.

10 Replies

Telnet 25

Then leave them a message.

Good point. My SMTP is a little rusty; guess I'll brush up on it.

It's also possible to put an IP address in brackets after the at symbol, e.g. [email protected][12.34.56.78] - but I don't know the chances that the receiving mailserver will actually accept that.

Lol - I had to try that. Gmail will send it out that way, but none of the 4 servers that I tested it on would accept it. 2 just dropped it. 1 bounced it. And 1 said it didn't allow smtp relay.

update: that was without the brackets. gmail will not send if the address has the ip in brackets

postmaster at mail.vanuatu.com.vu should get through to someone who could address the MX problems.

@Stever:

postmaster at mail.vanuatu.com.vu should get through to someone who could address the MX problems.
Yeah, should is the key word. That's a postmaster address at Telecom Vanuatu LTD, a commercial entity who runs the datacenter, but I'm trying to reach somebody at VuNIC, a not-for-profit that's a separate organization staffed by different people. They're both in the same industry on the same island, but TVL doesn't control VuNIC's DNS zone directly.

I did send a message as suggested above by typing an SMTP session into telnet, so we'll see if they get back. If not I'll try emailing TVL.

@vonskippy:

Lol - I had to try that. Gmail will send it out that way, but none of the 4 servers that I tested it on would accept it. 2 just dropped it. 1 bounced it. And 1 said it didn't allow smtp relay.

update: that was without the brackets. gmail will not send if the address has the ip in brackets

Interesting. while I knew it was an option (the RFCs include all kinds of weird address specs), I never actually tried it. It worked for me with the brackets, sending from mutt/sendmail on Solaris to postfix on CentOS. Didn't work without the brackets; sendmail rejected it with: 550 5.1.2 … Host unknown (Name server: 12.34.56.78: host not found)

if you are using postfix you could look at transport_maps. Other MTA's have similar features

Update: got through to them using the SMTP over Telnet workaround, and it's fixed. Apparently TVL was doing some kind of split-horizon DNS setup that went wrong, and everything looked OK to DNS clients on the island (ony one ISP), so they didn't notice it was broken on the rest of the Internet.

funkytastic - the email whisperer - lol

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