Re: [exim] Duplicate port 25 traffic to 2 destinations

On 5/1/06 8:55 AM, "John W. Baxter" <jwblist@???> wrote:

> On 5/1/06 8:18 AM, "etienne1" <etienne@???> wrote:
>
>> Hi, I am currently testing a mail filtering unit(for spam,virus..etc), and
>> would like to forward all the traffic on port 25 to a second destination in
>> order to test it.
>>
>> I've searched quite a bit and did not find the info to do this. AllIi found
>> is the way to divert some emails with a domain name filtering for example to
>> another MTA, but not how to duplicate the traffic to a second destination.
>
>
> If you are running a Linux distribution that includes iptables, you can
> probably do the duplication with an iptables setup (I can't help with that).
> Since you post by way of nabble.com, I can't work out from the message
> headers whether you are likely to have iptables or not.

Dave and Marc P are correct.

While iptables might well be able to divert a copy of the connection for you
(or not), the nature of SMTP would lead at best to a very confused server on
the other end of the connection.

I think you're stuck with testing with test sessions until you're willing to
go live with the changes, in at least short bursts.

What we have done in the past, which we can do since our mail processor is a
suite of Python programs, is have the initial program create the duplication
into the queuing system for the test version, with the output from the test
side back into Exim logged and discarded, and the processor logging
examined. But that won't work for SMTP-time filtering.

--John