This sounds like a job for an ESMTP option.
At 08:28 PM 1/19/99 +0100, Pavel Kankovsky wrote:
>SMTP conversation:
>----------
>> MAIL FROM:<verptest-@host1-@[]>
>> 250 ok
>< RCPT TO:<user@host2>
>> 250 ok
>< DATA
>> 354 go ahead
>< Subject: VERP test
><
>< .
>> 250 ok 916770426 qp 1077
>----------
>
>Delivered message:
>----------
>Return-Path: <verptest-user=host2@host1>
>Delivered-To: user@host2
>Received: (qmail 16270 invoked from network); 19 Jan 1999 18:27:09 -0000
>Received: from host1 (xx.xx.xx.xx)
> by host2 with SMTP; 19 Jan 1999 18:27:09 -0000
>Subject: VERP test
>----------
>
>Conclusion: qmail does not need to send multiple copies of VERPed message
>if the destination SMTP server runs qmail (or any other VERP-enabled MTA
>if such MTA existed).
>
>Of course, it needs to figure out whether a particular MTA supports VERP.
>
>--Pavel Kankovsky aka Peak [ Boycott Microsoft--http://www.vcnet.com/bms ]
>"NSA GCHQ KGB CIA nuclear conspiration war weapon spy agent... Hi Echelon!"
>
>
>
