We've recently put a graylisting spam filter at the edge of our campus network, but at my request the Listserv was left outside the filter because I was concerned that graylist processing of all the traffic coming in to the server would introduce delays that would somehow harm Listserv.

Has anyone out there put their Listserv behind a graylisting spam filter? The Listserv server has been getting hit pretty hard by phishing scams lately, which seem to be coming in under Listserv's net-wide spam radar. Currently our graylist is catching these spams but a few of them always seem to leak in through Listserv. I'd like to have Listserv moved behind the graylist filter if it won't harm the operations of the server. We are a backbone server running in networked mode.

-aht