2010/02/05

IPv6 email autoreply facility

In the past two days, I was busy setting up an autoreply facility for IPv6 email. My experience is that if system administrators set up their IPv6 SMTP servers, it is difficult for them to find IPv6-enabled mail servers for mail transaction tests. Even if they found some, how can they make request to ask some body to help the test. What I try to do is to set up an IPv6 only SMTP server, dedicate an email account with autoreply so that other system administrators can perform IPv6 mail transaction without bothering to call me.

Luckily, I got the domain “v6-mail.com”. Logically, the email account for autoreply function is “autoreply@v6-mail.com”. I continued to configure my DNS to handle MX and AAAA records. Next, I installed Postfix on a dual-stack Linux server with 6to4 tunnelling and I forced Postfix to listen to IPv6 address only. Then came the most difficult task. How to enable autoreply function on the user “autoreply”. I used .forward and vacation but the problem is vacation only reply to sender once within a day and any other subsequent email received from the sender will not be replied. I recalled that flushing vacation.db will clear all previous locked records so I added an cron job to do “/usr/bin/vacation –I” on a per minute basis. This solved all problem plus it added anti-spam feature. If the sender sends more than one request to “autoreply@v6-mail.com” for testing, only one autoreply message will be delivered within a minute.

All these bundled together work up to my expectation. I am very glad that I have developed something helpful to the IPv6 community.

12 comments:

Damien Clauzel said...

Very convenient. Thank you.

Anonymous said...

Very usefull! Helped fix me some problem in Courier mail server!

Thanks.

How about setting webserver on v6-mail.com with small webpage, which will take address and captcha, to test IPv6. Will make it even easier :)

Anonymous said...

Thank you very much. I think this is the first time my SMTP server has actually received a test connection over IPv6.

Anonymous said...

Thanks Warren! Your smtp service really help me to test my newly configured SMTP server.

Chris Wiegand said...

Just used this to test my Cygwin-based Exim IPv6 enabled server - HE.Net is taking forever to do the MX/AAAA lookup but this let me ensure it was correctly setup right away! Thanks SO MUCH! All of the online tools are IPv4 only...

warrenkwok said...

I have developed a web-based v6 email autoreply tool at the URL www.v6-mail.com accessible by v6 only. My blog post related to this is at http://warrenkwok.blogspot.com/2011/06/web-based-v6-email-autoreply-tool.html.

Anonymous said...

Page and responder is not working....
Waste of time. :(

Martijn said...

Thanks for providing this service.

It would be even more useful if you could attach the headers (or complete message) of the original mail in your reply, so I can see how your mailserver sees mine.

Anonymous said...

Thanks for the autoresponder. However, the reply was rejected at my side:

<>
450 4.7.1 Client host rejected: cannot find your reverse hostname, [2401:300:0:1::8080];
<>

I'm still not sure about anti-spam best practices and ipv6, but you might want to set up a proper PTR record.

warrenkwok said...

Reverse lookup of the IPv6 address is properly entered by my serving ISP. There should be no more email rejection.

Anonymous said...

connect from ns1.i3way.net[202.81.252.116]
Is it normal that the autoreply comes with ipv4 ? I wanted to test the reception with IPV6 too ;-)

warrenkwok said...

My local side runs with dual-stack now. If the remote side is also a dual-stack config, v6 channel will always be selected first. However, if the v6 path is not available or there is a routing error, then the email message will fall back to v4 path.