Re: Still not possible to send mail to domain libc.org

[Harald Becker <ralda@gmx.de>]

On 23.04.2015 23:55, Harald Becker wrote:
> Hi Rich,
>
> extending my search on qhe net I found the following:
>
> All of the senders experiencing the bounced messages mentioning cname
> lookup failure appear to be running the qmail mail server software.
>
> Qmail, if not using a third party patch that was written in the late
> 90’s, has an issue sending to domains whose name servers respond to DNS
> queries of type “ANY” with more than 512 bytes of data; that is a bug in
> qmail and the author has never fixed it because he wants you to use his
> DNS server software which also eliminates the issue in a different way.
>
> Google’s name servers do respond to queries of type “ANY” with more than
> 512 bytes of data, so when an unpatched qmail server tries to send an
> email to a domain whose lowest cost MX record ends in .google.com, qmail
> is going to do a DNS query of type ANY against one of google.com’s
> authoritative name servers, get back more than it can correctly handle
> and defer repeatedly until ultimately bouncing the message with that
> cname lookup failure…

Sorry I forgot to add the link:

https://productforums.google.com/d/msg/apps/mIGTQVZiFxo/ULesU7hOo6wJ

>
> Harald
>