>We are looking at using Imail and I just had a question about peering. When
>an email is send to a domain which has multiple Imail servers using peering.
>
>Is the complete message sent to the first server and then passed onto the
>next server because the user wasn't found on the first server?
Yes, a peer looks at the "RCPT TO: @peered-domain" and decides "it's
for us", even if it's not for itself, and accepts the entire msg. If
the receiving peer doesn't have the account, then it starts sending
SMTP VRFY commands to the other peers until it finds a home for the msg.
So in a peer group of N peers, only (1/N x 100) % of the msgs are
delivered to the right box.
ie, in peer group of 4 boxes, 7,500 out of 10,000 msgs would end up
on the wrong box. Of those 7,500 msgs, the receiving box would have
2/3 of its VRFY probes to the other peers fail. That's 5000 bad
VRFY's. For 2 peers, Imail peering isn't too bad, but for 3 or more
peers, it appears to me that high-volume peers would DoS themselves
while trying to find the right peer for a msg.
Imagine a peer group of 10 boxes, where 9000 out of 10000 msgs would
be mis-delivered and it would take an avg of 8000 bad VFRY's to find
the right peer. hmmmmm
>Or does the server sending the message to our domain query all the servers
>in the peering list until it finds that user and then sends the complete
>message directly to the server which that user is listed on?
yes.
Len
http://BIND8NT.MEIway.com : Binary for ISC BIND 8.2.3 T9B for NT4 & W2K
http://IMGate.MEIway.com : Build free, hi-perf, anti-spam mail gateways
Please visit http://www.ipswitch.com/support/mailing-lists.html
to be removed from this list.
An Archive of this list is available at:
http://www.mail-archive.com/imail_forum%40list.ipswitch.com/
