On 2009-09-27 Erick Calder wrote: > On Sep 27, 2009, at 12:53 AM, LuKreme wrote: >> On Sep 27, 2009, at 0:53, Erick Calder <e...@arix.com> wrote: >>> if the message were for no-ex...@arix.com then it gets rerouted to >>> n...@arix.com which also doesn't exist and therefor bounces. >> >> Yes, it bounces. This makes you a backacatter source. This is bad. > > but doesn't my postfix server bounce by default when receiving a mail for > an inexistent address?
No. In that case it rejects the mail¹, meaning that the response goes back to the sending MTA instead of going to the address given in the envelope from (which is usually forged in case of spam mails). Regards Ansgar Wiechers ¹ At least that's what it *should* do, unless you configured it to accept all mail first, and check later whether it can actually deliver it. -- "All vulnerabilities deserve a public fear period prior to patches becoming available." --Jason Coombs on Bugtraq
