[Mailman-Users] Mailman posting question

Dragon dragon at crimson-dragon.com
Fri Aug 1 19:04:45 CEST 2008

Mark Sapiro wrote:
>Dragon wrote:
> >
> >MTAs are designed to deliver mail to the correct host based on the MX
> >record for a given domain.
>Except in cases where the recipient domain is one of the MTA's 'local
>domains'. In that case, the mail is delivered locally without ever
>consulting DNS.
---------------- End original message. ---------------------

Which was sort of implied by the rest of my post, I didn't state it explicitly.

But this is true of any network traffic at the TCP/IP and even at the 
MAC layer. If it is local, it doesn't go out on the wire even though 
you may be sending it to the physical address of a configured 
interface. The network stack is smart enough to know that it should 
just pass the traffic in memory instead of sending it on an actual 
interface, it essentially, and transparently, substitutes "localhost" 
for the address because it knows how to get there directly.

Basically, the principle of "shortest path" is used. How exactly this 
gets done in an individual MTA is based on how it is designed and 
configured. Since I don't know the exact details of any of them, I 
will leave any discussion of how they route local traffic to those 
who do know.


  Venimus, Saltavimus, Bibimus (et naribus canium capti sumus)

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