Hi Toralf, on Tue, 06 Jan 2004 10:58:47 +0100 you wrote:
> We usually configure our MUAs to send e-mail via SMTP to localhost,
...
> Now, this seems to cause problems with some blacklists etc. on the net;
> apparently they think "localhost" is evil.
> 1. Why?
What I *suspect* is happening (it's hard to tell without an example
bounce, so this is obviously speculation) is not to do with "blocklists"
but that some people are blocking you based on "HELO localhost", for one
or more of the following reasons:
- "localhost" isn't a FQDN
- "localhost" doesn't match your reverse DNS
- "HELO localhost" can be an indicator of a badly-configured machine
- they don't like the specific string "localhost" in HELO for a reason not
in the above
> 2. Is there a good way to avoid including this localhost reference?
> I guess updating received_header_text is a possible solution
If, as I suspect, people are blocking your HELO rather than a reference in
the Received header(s), changing the Received headers won't help - the
solution is to change your machine's hostname, so that it consequently
says "HELO <something.useful>".
> 3. Should I configure the mailers differently? Note that the ones we
> are using typically don't allow mail to be sent via local (MTA
> exec), and I'd rather not hardcode a hostname as I want the config
> to be completely portable.
If you leave primary_hostname unset in the Exim config, it should pick up
whatever hostname your machine is using, in which case it shouldn't reduce
the portability of your config. It does, of course, mean deciding on a
specific hostname for each machine.
Hope that helps.
Tim
