Hi, > > I would question how "real time" that would be for every email for > 6k+ > > domains. If a few have a large client base, or are expecting > responses > > from a mass emailing, it might start to take a *while*, unless you've > got > > pretty heavy duty equipment and networking. > > It's the same thing the downstream server is going to have to repeat in > just a > moment anyway, but this time it doesn't have to do the other steps. If > you are > close to capacity already it might push you over the edge - and be > worth > scripting a way to maintain that frontend virtuser table that makes it > a > near-instant hash lookup for the relay sendmail. But for the relay it > will be a > win either way to avoid the much heavier load of spam-scanning stuff to > invalid > recipients and making the downstream servers construct bounces. I hadn't looked at it like that, you may be right, the reduction in scanning may provide enough capacity to handle the additional workload from perl. I think that I would prefer to have sendmail do the "rcpt to:" rejection utilising a map as this I think will be the fastest method, so I'll check out the virtusertable approach. Thanks S.