Hmmm... so say that we have three imail machines peering... each running web
messaging as well... a request comes in to webmail on box 1 as it is the
first to answer but the mailbox is on box 2. It can still handle the session
right? It knows where the mailbox is and retrieves the messages accordingly?
Or how would that work?
Bryan Andrews
Senior Web Administrator
Cox Communications, Inc.
-----Original Message-----
From: Len Conrad [mailto:[EMAIL PROTECTED]]
Sent: Monday, February 28, 2000 1:26 PM
To: [EMAIL PROTECTED]
Subject: Re: [IMail Forum] Peering Questions
Peering means that both servers share the same MX priority
level for
incoming mail only, but only one of the two (or ten )
servers has any
specific mail account. Any peer server will accept the
mail, and then
forward to the correct peer using the SMTY VRFY command (has
to be
enabled). This does give a backup mail server / redundancy
aspet, also,
Peering has no advantage on heavy-lifting of outgoing mail,
POP3, or Web
Messaging, all of which have to be handled by the specific
Imail server
that holds a specific Imail account.
The real nasty work of SMTP job is not receiving mail, but
in sending it.
Imail has to spawn an SMTP process, which then looks up the
destination ip
in DNS, wait for that to come back, tries to contact the
mail destination,
if unreachable, it retries with secondary mail destination,
if fails,
queues the mail for later attempt, etc, etc. if reachable,
it shakes
hands, blah, blah, delivers the mail, all at typically
erratic internet speeds.
To offload all of that outgoing grunt work to another
machine, use the
Imail "deliver through a gateway", where the gateway is at
best on the same
local subnet, and you give the gateway's ip address so Imail
doesn't have
to do DNS lookups to find the gateway's ip address. Imail
drops the mail on
the outgoing gateway ip address quickly and reliably, gets
back to work the
more user-reactive tasks such as POP/IMAP and Web messaging
sessions.
Len
=====================
>Can anyone out there explain the relationship between 2
peered IMail
>servers? how much load balancing can they accomplish or
does the second
>server just handle the occasional overflows and downtimes
via a secondary
>MX?
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