Re: [cobalt-users] [RAQ4] SMTP E-Mail Forwarding

[Jens Kristian Søgaard <jens@xxxxxxxxxxxxxxxxxxxx>]

> I have a RAQ4 with a virtual host. I want to forward all the e-mail
received
> for this host to an Exchange server at the client site. The problem is
that
> the Exchange server is not connected to the Internet all the time although
> it does have a fixed IP address. So the Raq4 box needs to queue the
messages
> until the Exchange box comes on-line (every hour or so).
> I know this can be done as other ISP's do it

Setup DNS so that you have two MX records for the site. One (with lowest
cost = high priority) that points to the Exchange box. The other (with
highest cost = lowest priority) that points to your RaQ4.

You would then like your Exchange box to be able to retrieve all queued
emails. This is called ETRN - and when that command is given to sendmail, it
simply "flushes" it's queue - and sends all emails to your Exchange box.

I.e. configure your Exchange box to act, if it was an emailserver connected
24x7. Except ofcourse for the fact, that you should have some software in
place, that runs the ETRN command whenever it connects to the net (Exchange
5.0+ supports this).

You need to setup your sendmail so that it will relay for the domain(s) in
question. If you do not like "double administration", you could consider (!)
using the "relay_based_on_MX" feature of sendmail (where it checks DNS for
MX records, and chooses to relay or not based on this).

You can read about the specifics of ETRN in RFC 1985. For more information
about configuration check www.sendmail.org or the Bat book.

--
Jens Kristian Søgaard, Mermaid Consulting I/S,
jens@xxxxxxxxxxxxxxxxxxxx,
http://www.mermaidconsulting.com/