On 8/6/2009, Santiago Romero (srom...@servicom2000.com) wrote: > By adding the following to my main.cf, I'll check RCPT TO addresses > against primary MX, except when PRIMARY MX doesn't answer. In that case, > I'll accept any destination for my relay_domains list, just like I was > doing before adding those lines: > > address_verify_map = btree:/var/lib/postfix/verify > address_verify_positive_refresh_time = 14d > unverified_recipient_defer_code = 250
You are correct, but this is NOT the recommended way... Don't change the unverified_recipient_defer_code to 250... leave it at its default 450. This way you will not be a backscatter source ever, and the worst that will happen if their primary MX is down is some mail might be delayed a little. Also, if I'm understanding the way this works correctly, you can also use the address_verify_map parameter to cache hits (both negative and positive), which will allow you to continue accepting mail for recipients who are still in the cache even if the primary MX is down. http://postfix.mirrorspace.org/postconf.5.html#address_verify_map -- Best regards, Charles
