Anycast provider for SMTP?

Mon Jun 15 18:09:11 UTC 2015

On Mon, Jun 15, 2015 at 1:50 PM, Joe Hamelin <joe at nethead.com> wrote:
>   My solution will be to place a load balancer in a hosting site
> (virtual, of course) and have it provide HA.  But what about HA for the
> LB?  At first glance anycasting would seem to be a great idea but there is
> a problem of broken sessions when routes change.
>
> Have any of you seen something like this work in the wild?

Anycast + TCP = much pain, for reasons which should be obvious. It's
on the near side of impossible, but the far side of impractical. You'd
spend a lot of money with some high-price software developers getting
it to work.

> I have a mail system where there are two MX hosts, one in the US and one in
> Europe.  Both have a DNS MX record metric of 10 so a bastardized
> round-robin takes place.  This does not work so well when one site goes
> down.

Not sure why you'd have problems with this since it's a primary
operating mode that SMTP was explicitly designed for. Can you
elaborate on the kinds of trouble you've experienced?

Regards,
Bill Herrin

-- 
William Herrin ................ herrin at dirtside.com  bill at herrin.us
Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>