Re: [courier-users] Courier prefere ipv4 before ipv6?

Sam Varshavchik wrote:
> Marco Balmer writes:
>
>> Hi
>>
>> My Courier-MTA has a internet connection to ipv4 and ipv6. If it send
>> a message
>> to a other MTA which has ipv4 and ipv6, courier send this message over
>> ipv4.
>>
>> Why is this so? I think it should send trough the ipv6 connection?
>
> That's just how MX records are processed. Why does it matter?

I think, that Marco meant that if hostname, pointed to by MX record, has
_both_ v4 and v6 addresses, courier preffers v4 address (did not checked
if that's true).

According to v6 documents, when host has both - v6 and v4 - addresses
programs should try v6 first, and only on failure try v4 (because
otherwise migration to v6 will never happen).
http://tools.ietf.org/html/rfc3484#section-10.3

That's theory. I never investigated how things are in SMTP world. But
just by browsing the web, number of times I suffered from the fact, that
admins add AAAA record to their production service names, while service
is not runing on v6 interface, or not accepting connections from 6to4
addresses, or have other issues with v6. This sometimes leads to
half-minute wait times for ff to load at least something! And that
happened with sites dedicated to v6 matters! Guess what happens when v6
starts getting steam!

Half of a minute timeout for SMTP would be less an issue than for HTTP,
imho. But, if v6 will be preffered, fallback to v4 addresses absolutely
must be implemented.

--
Aidas Kasparas
IT administrator
GM Consult Group, UAB

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?p...rge&CID=DEVDEV
_______________________________________________
courier-users mailing list
courier-users@lists.sourceforge.net
Unsubscribe: https://lists.sourceforge.net/lists/.../courier-users