Mark Martinec <mark.martinec+post...@ijs.si> writes: > On Sunday August 23 2009 04:10:06 Dave Täht wrote: >> What I found after fighting with an exchange server that what seems to >> work best is assigning my first mx host to be ipv6 only, and my fallback >> to be a mx ipv6 and ipv4 host. > > My choice is to have the first MX have both the IPv6 and IPv4 addresses, > but have a lower priority MX be IPv4-only. This way it should provide a > fallback connectivity even if some mailer which thinks it has an IPv6 > connectivity but doesn't, then fails to walk through multiple records > of a multihomed host name. (even though RFC 5321 requires to try > at least two records).
In my case, my first mx record is my laptop which has postfix configured to listen and send on IPv6 only. For sending mail, if it can't get through, it falls back to forwarding via IPv6 to the secondary, smarter host, which is listening on both IPv4 and IPv6. Replies to teklibre.org try that IPv6 mx record first (I hope), then fall back to the smarter host. This brings back an age of direct email connectivity for all the IPv6 hosts on my fairly widely geographically spaced network. Mail gets through as fast as IM (or faster), with a minimum of men in the middle, over IPv6 whenever possible. I still have to get reverse DNS to resolve, working on it... (the 8 hosts I have exchanging mail this way use certs to identify and authenticate themselves currently) This leaves the problem of dealing with non RFC 5321 compliant hosts, but to heck with them, and so far, I haven't had anyone complain that they can't get mail to me (I am continuing to experiment, however). > > Mark > -- Dave Taht http://the-edge.blogspot.com
