Re: [exim] Rotating SMTP Outgoing IP addresses - SOLUTION

Dave Lugo wrote:

>
> I think the Rotating SMTP Outgoing IP addresses is a bad idea.
> You should already be using parallel sessions, so the pipe is
> nearly full, I'd hope. If you can shove additional items over
> the same session, that helps too (though I don't know exim's
> specifics in this area). You want to rotate IPs, send from
> multiple physical hosts.
>

I hate to pursue this thread but rotating IP adresses may have some
legit uses, that's why Marc's thread interested me.

Example 1:
When I got my 2 new servers for my personal purpose, they were allocated
2 physical addresses and 2 virtual ones using CARP in a load balancing
scheme. For an unknown reason the 2 physical addresses were wrongly
listed at sorbs as dynamic IPs. So I thought on sending through virtual
IPs, and put one virtual IP for outgoing on each host. The problem being
the two IPs were using CARP in load balancing mode, so using a hash for
the routes. This meant that 1 IP on 2 were unreachable from one
particular host and the same for the other host but reversed. If I could
have rotated on both IPs, I wouldn't have noticed the problem with CARP
and there would have been no overly delayed mail.

Example 2:
skynet.be is using a "new" stupid antispam scheme on which you are
delayed for some hours if you ever make more than 4 concurrent
connections to their servers (I know it is extremely stupid, but that's
not the point and thats about the same as rate limiting). skynet.be
being the leader ISP in Belgium, there are a lot of mails going to their
servers. So if 4 people in a firm sent them "large" mails at about the
same time, no mail would pass for days. Their helpdesk being
particularly unhelpful, I had to find a way bypassing their stupid
scheme to have mails delivered. Rotating IPs would have been one
solution. I am using queue_smtp_domains = skynet.be, but this only
solves the problem partially as they host mail servers for domains
besides skynet.be and this delays mails.