Author: James P. Roberts Date: To: David H. Lynch Jr., 'Exim users list' Subject: Re: [Exim] [Exim]Routing around blocking servers
> I have two internet connections. One on a standard multiple > fixed IP 128K business class DSL line and one on a floating IP cable. My > outbound routing favors the cable as it is dramatically faster, and as I > wish to conserve bandwidth on my DSL connection. I have email users
> that frequently need to send very large files as attachments, a few of
> these will choke my DSL connection.
>
> I am not sure whether various ISP's policies have changed, but I
> am starting to get an increasing number of bounces because a few major
> ISP's are now blocking email from cable IP's. In some evil twist, they
> serve a disproportionate percentage of the clients that we send large
> files to.
>
> Is the a way to persuade exim (4.x) to send e-mail for certain
> users via a specific interface or IP ?
>
As far as I know, unless you have a "business class" cable connection
(which I presume should come with a static IP, and therefore you
probably don't have it), then the OUTBOUND speed is usually throttled by
the cable company (I think to 128K in the case of my local cable
company, for example), plus, they typically have rules against putting
servers on non-business-class cable connections. What I am trying to
say is, there is a very good chance that you want to use your DSL for
sending large files OUTBOUND. On the other hand, you would want to use
the cable connection for INBOUND traffic, as it is dramatically faster
in that direction.
All that said, I'm pretty sure that, yes, you can specify an IP (and
port) to use for any particular Exim router.
To do this, specify the cable IP/port for your clients to connect to
your SMTP server (which is tricky, no doubt, if it is not a fixed
IP...). Then, specify in your Exim config to send outbound on the DSL
(fixed IP).