Author: Patrick Starrenburg Date: To: exim-users Subject: [Exim] Re: Example of legit email rejected by testing on reverse IP lookup
"James P. Roberts" <punster@???> writes:
> It is a static IP block, of course.
Are you sure... your address 64.105.159.234 shows up in my tools as belonging
to one contiguous address range 64.105.0.0 - 64.105.255.255 which means it
is most like part of an ISP's dynamic addresses. Unlike someone booking a /24
to /29 Internet IP address range. This puts you (along with a lot of people
with DSL/cable connections) in that 'twilight' zone of not really a 'business'
class connection but maybe still running a business on it!
You cannot get away from the situation that sites/MTA's out of your control are
going to consider your host to be suspect and maybe play it safe and block you.
This is irrespective of whether your ISP (this week) is returning your reverse
lookup OK, things like MAPS work on *IP addresses*. Also some sites (as has
been said) look at reverse IP and if it has any IP address range data in it
block the host, whether we agree with that or not will not necessarily change
the situation.
So what's to do -
Two considerations - mail in and mail out. As long as your ISP does not block
incoming traffic on port 25 on their net address block then your incoming is
OK. Outgoing you either:
* redirect everything to smart host - your ISP's relay server or;
* send mail out directly, wait for rejects then put those domains into list
then make a manual route to go before dnslookup router to send to ISP's mail
relay server.
this will try all domains in '/the/file/name' if domain not found will pass
through to next router - dnslookup.
To have this happen automatically... hmmm more difficult. Exim would have to
selectively process the error and know the difference between real mail
failures and failures due to this issue. This would be *after* the fact of it
having chosen a router and processed message.
