First, hello to the list and the opensmtpd devs- thank you very much for this great mta. I've been building postfix gateways on openbsd for maybe close to 10 years and have been following opensmtpd with great interest.
I'm migrating a set of postfix gateways to opensmtpd. The role of the gateway is only to filter and relay email to internal (Domino, in this case) mail servers. The goal of my question here is to reject invalid recipients at the gateway. In the past I have used a canned perl script to generate a postfix table by performing an LDAP query from the mail server's directory (postfix: relay_recipient_maps). I'm not a perl hacker and this has stopped working at recent OpenBSD releases. But it can be replaced by the more elegant reject_unverified_recipient - which is a pre-check of the recipient address at the relay destination and rejects the email if the recipient doesn't exist. So far my searches of the openbsd and opensmtpd misc archives as well as the opensmtpd.conf man page haven't revealed a similar way to achieve this. I'm tempted to not bother - for invalid recipients the gateway will accept the email then immediately generate and send a NDR - I can't be the first to use opensmtpd as a gateway like this. But in that case I'm curious what have others done about the potential for the gateway to be a source of backscatter spam? Thanks, Andrew
