On 30/03/06, Adam Funk <[EMAIL PROTECTED]> wrote: > On 2006-03-30, Peter Bowyer <[EMAIL PROTECTED]> wrote: > > On 30/03/06, Adam Funk <[EMAIL PROTECTED]> wrote: > >> On 2006-03-30, Nigel Wade <[EMAIL PROTECTED]> wrote: > >> > >> > That only works for mis-configured MTAs. A properly configured MTA would > >> > reject > >> > a message destined for a non-existent recipient. It would not accept it > >> > and then > >> > generate a bounce message. > >> > >> But when MTA(n) rejects a message that MTA(n-1) is trying to relay, > >> MTA(n-1) has to bounce it, right? > > > > MTA(n-1) shouldn't accept messages to invalid recipients in the first > > place. If it has no direct knowledge of valid recipients, it should do > > callouts. > > I understood those weren't reliable because (there may be other > reasons?) in many cases MTA(n) is configured not to give out that > information because spammers could use it.
The usual use case here is a 'border' MTA receiving mail for a known list of domains and forwarding to inner mailbox servers. In those controlled circumstances, recipient callouts are just fine. They shouldn't be used to indiscriminate destinations - but an MTA shouldn't be relaying for indiscriminate destinations either. Peter -- Peter Bowyer Email: [EMAIL PROTECTED] -- ## List details at http://www.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://www.exim.org/eximwiki/
