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Exchange
- SMTP
- ISP
Issues -
Here
are some common problems with solutions you may encounter with
your ISP.
| Problem: |
My ISP
freaks out when I mention Microsoft or Exchange and won't talk to
me anymore. |
| Solution: |
Omit those two words from the discussion. Simply tell the ISP you
have an SMTP mailer that you want to have receive your mail.
|
| Problem: |
My ISP is running
Exchange. How do I work with that? |
| Solution: |
Your ISP
must be running Exchange 5.0 SP2 or 5.5 SP1 (or later). This
supports the ETRN Mail Retrieval method. They can specify
that mail be "Queued for ETRN" to prevent unsuccessful
delivery retries from consuming system resources. |
| Problem: |
My ISP doesn't like
retrying my queued mail so often if I'm not dialed up. |
| Solution: |
If your
ISP runs sendmail, have them look at http://www.wizzy.com/
wizzy/mail
for a description of how to set up their sendmail for multiple
queues. The description there talks about the finger method of
dequeueing, but ETRN would work, too. More about this on the Exchange
Dequeueing Methods
page. Sendmail 8.8 also now supports the configuration
of a separate delay time for the first retry. This may also
be useful to the ISP. See if you can come to an agreement
with your ISP on an acceptable number of queued messages before
you convert to a dedicated account. Periodic monitoring of
this is easy, both for the ISP and you. |
| Problem: |
My ISP doesn't like
queueing because "This doesn't scale. The queue is one
directory." |
| Response: |
The queue
is one directory by default. You can make it as many directories
as you want (with sendmail). If the ISP really gets this many
customers doing this, then putting a little brain power into a
creative solution would be worthwhile. If they only have you, they
should shut up - it's a non-issue. |
Problem:
(continued) |
"Guess
what happens when 500 domain customers (we have well over 1000) do
this, and each of them get 100 emails queued." |
| Response: |
At that
point you redesign the MTA to support the traffic model of your
customers. It's not that difficult and is exactly what folks like
AOL have had to do. This solution is really designed for the
customer who only gets 5-10 emails every 1-4 hours. There are
quite a few people like that. Run the numbers on randomized
dial-in, weighted for business hours, etc. and the load is VERY
SMALL. |
Problem:
(continued) |
"That's
50,000 files in a directory. The traversal time to search and
attempt delivery from the queue on each of these will be measured
in *hours*." |
| Response: |
Perhaps.
But we're talking about one customer who wants to queue 5-10 email
messages. If there are 100+ messages queued in one queue interval
(a couple of hours I would guess), then the customer (you) needs a
dedicated connection. This also may be an issue for the ISP
regardless of queueing. It has been much discussed on the
sendmail newsgroups as a problem for all large ISP's. |
| Problem: |
How do I configure
sendmail to queue mail? |
| Solution: |
Harker Systems has a great
reference on how to configure sendmail for dial-on demand
operation. Including a pre-made m4 file to build into your
sendmail config.
http://www.harker.com/sendmail/
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