In article <19990419090038.B23596@???>,
James FitzGibbon <james@???> wrote:
>* Philip Hazel (ph10@???) [990419 06:12]:
>
>> I think we have to distinguish "LMTP over TCP/IP" and "LMTP over
>> file-descriptor". The former could no doubt be done by a flag in the
>> smtp transport. However, given the existence of the latter, I think I
>> would prefer to have an entirely separate lmtp transport which handles
>> both cases via some suitable options, e.g. you set either
I am unsure of what the latter is! LMTP is defined by RFC2033 and is
explicitly a network protocol.
>> lmtp_command = xxxx
>>
>> in order to run a pipe, or you set
>>
>> lmtp_hosts = list of hosts to try
>
>That would address the issues that I brought up, but it also means that a
>lot of code would be copied from both the pipe and SMTP transports into this
>new transport. Granted, I can't see SMTP changing that much in the future,
>but it does mean that code changes would have to be made in two places.
>
>> I guess port= would be needed too. Maybe only a single host is needed.
>> That would simplify the code quite a lot.
>
>"port =" would be needed, but strangely the RFC doesn't say which port
>should be the default. The only mention of a port is that it shouldn't run
>on port 25.
Port is required. There is no recommend port, probably because this is
designed as a local distribution mechanism. Local selection of the port
to be used is sufficent for the requirements.
While supporting a single host solves a problem, it allows you to move
mailboxes from the MTA system to a separate system; it only improves things
incrementally.
Allowing multiple hosts allows the system to be scaled and implemented
with redundancy at the front end.
Consider something like the following. Multiple front end MTA's with
identical configurations and accessed through one of the common methods for
multiple servers (round robin dns, cisco local director, multiple equal
weight MX records etc). Each capable of delivering to multiple mailbox
servers.
For POP only mailbox servers I'm estimating about 2-1 ratio of mailbox to
MTA servers. For IMAP mailbox something like 4-1.
--
Stuart Lynne <sl@???> 604-461-7532 <http://edge.fireplug.net>
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