> Is there an easy way (preferably without modifying source
> code) to configure exim to allow an underscore in a RCPT
> domain name? I don't mean only in EHLO, but really in the
> recipient domain name (address like <ddts@tmn_00.domain.tld>).
>
Yep. In fact how to do it is in the FAQ on
www.exim.org in a slightly different
form. But to make life easy for you:
Q0732
Question
I would like to either warn or deny when a host uses an underscore in the EHLO
command.
Answer
First, set
helo_allow_chars = _
This tells Exim not to reject the EHLO or HELO command immediately. Once you
have done that, you can test for the underscore in an ACL. For example, to log a
warning for hosts in your LAN, and reject for other hosts, you could do
something like this:
deny message = Underscores are not valid in host names
hosts = ! +lan_hosts
condition = ${if match{$sender_helo_name}{_}{yes}{no}}
warn log_message = Accepted underscore from [$sender_host_address]
condition = ${if match{$sender_helo_name}{_}{yes}{no}}
---
So, as you can see, it's the helo_allow_chars config you need to alter.
John
