I'm using an accept hosts file lookup for use in white-listing some
hosts.
accept hosts = ${if exists{CONFDIR/local_host_whitelist}\
{CONFDIR/local_host_whitelist}\
{}}
I realize IP addresses are better, but if I have a list of domain
names in that file and one of them fails to lookup then processing
stops and the accept fails. That is if my list looks like:
invalid_domain.com
exim.org
Then when exim.org connects it is not accepted because invalid_domain.com
didn't lookup and processing of the list stopped.
Is it possible to ignore the failed dns lookups until the *entire* list
is processed? In the example above, ignore that invalid_domain.com
failed to lookup and then test for a match on exim.org?
BTW -- this came up due to a problem with sender verify. I know it's
a debatable practice. I've been using it for a year or two on a few
small domains and it's been a huge help.
But, about once or twice a year I have a host that send out legitimate
mail with invalid envelope sender addresses (once that can't be sent
mail) and I need to white list them.
I'm not clear from my scan of rfc2821, but are senders required to
use valid envelope sender addresses? If they really don't want
bounces back would a null sender be more appropriate than using an
invalid address?
The latest one sends mail on behalf of others. They send an invalid
local part of the envelope sender. They use that same address in
their From: header. Then they place a valid address in the Reply-To:
header (which also matches the To: header).
They claim the mail is fine because the envelope sender includes a
valid domain name and also that they include a valid Reply-To:
header. My spam filters don't agree. ;)
--
Bill Moseley
moseley@???
