This is probably obvious to everyone in the universe but me, but I was having a problem where my outbound email was being scanned by sa-exim, in addition to the desired scanning of incoming email.

The trick is in setting your SAEximRunCond in sa-exim.conf correctly. This is probably documented somewhere, but I totally missed it. In any case, assuming you want to skip scanning of email originating in your local network (e.g., IP address of 10.3.2.0/24) and that you changed the secret SA-Do-Not-Run header’s name to SA-Do-Not-Think-Of-Running, you would use the following line in your sa-exim.conf:

SAEximRunCond: ${if and {{def:sender_host_address} {!eq {${mask:$sender_host_add
ress/24}}{10.3.2.0/24}} {!eq {$h_X-SA-Do-Not-Think-Of-Running:}{Yes}} } {1}{0}}


Voila, outbound emails are no longer checked. Of course, if you are sending spam, please do not make the above change, but instead please swallow whole six to ten large, unpeeled pineapples.