archive · Ipv6 · Routing · Unix
IPv6 services on suspicious
Finally got around to enabling IPv6 on postfix for suspicious.org. For the longest time the IPv6 tunnel was up to Hurricane Electric, and yet aside from ping6, traceroute6, and the webserver, we weren’t really using production IPv6 services. I think the real killer app on Internet is still email even if it is pale in comparison to the bandwidth of p2p traffic flows; without email being seamlessly carried over IPv6 networks, we don’t have a chance in hell of converting the masses to the new protocol. My main goal is to provide all the same services on ipv6 as we do on ipv4 and then when I have some time I will setup some v6-only services that create an incentive for the switch.
Postfix is now fully IPv6 enabled. Our main box, inanna is running Linux and we have SIT interfaces for the IP-IP tunnels back to the tunnelbrokers. If speakeasy starts providing native IPv6 services I would easily switch over to a dual stack setup with them, in the meantime the tunnelbroker service is in NYC and the round trip time is less than 15ms from our box. Not too bad.
Setting up Postfix for IPV6 services is as simple as this statement in main.cf:
inet_protocols = ipv4,ipv6
The hard part after setting this up and restarting Postfix is finding an IPv6 SMTP server on the Internet. I would love to see some stats about reachable IPv6 SMTP servers because most of the sites I checked that even talked about IPv6 did not turn up IPv6 SMTP. That being said, after some digging, I found that the Pittsburgh Supercomputer Center (psc.edu) has IPv6 enabled MTAs and I tested some random addresses at their server, and hoped for a bounce message with some information that indicated the message was sent via IPv6:
<[email protected]>: host mailer1.psc.edu[2001:5e8:1:3a::64] said: 550 5.1.1
<[email protected]>… User unknown (in reply to RCPT TO command)
Reporting-MTA: dns; dns.suspicious.org
X-Postfix-Queue-ID: 68F217CE4
X-Postfix-Sender: rfc822; truman@suspicious[nospam].org
Arrival-Date: Sat, 24 May 2008 04:16:10 -0400 (EDT)Final-Recipient: rfc822; [email protected]
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; host mailer1.psc.edu[2001:5e8:1:3a::64] said: 550
5.1.1 <[email protected]>… User unknown (in reply to RCPT TO command)
Then I wanted to very the outbound message from our MTA to their MTA was sent via IPv6, doing this I just checked the logs:
[root @ inanna : /etc/postfix]>grep smtp /var/log/maillog | grep “\[2001"
May 25 00:24:57 inanna postfix/smtp[8108]: 6781615C6B: to=<[email protected]>, relay=mailer1.psc.edu[2001:5e8:1:3a::64], delay=2, status=bounced (host mailer1.psc.edu[2001:5e8:1:3a::64] said: 550 5.1.1 <[email protected]>… User unknown (in reply to RCPT TO command))
I haven’t yet testing inbound IPv6 to our MTA, but I presume it is working because I have setup A and AAAA records for the MX record for our domains. Subscribing to a mailing list that uses IPv6 MTAs should be a good test.
Originally published on truman.net. See the archived copy.