On Mar 6, 6:32 pm, bal...@msmu.ru wrote:
> Good day.
>
> Sorry if this question is mentioned in some sendmail FAQ, but I've
> been searching Internet for several days and I can't find the
> solution. I'm a sendmail newbie, I was working with Qmail till recent
> time.
>
> However, now I have a sendmail server and I cannot figure how to
> achieve this:
> I have DNS MX entry pointing to an external smtp server (let's name it
> mx.example.com, it's IP is 11.11.11.11) This server accepts messages
> for @example.com and forwards them to sendmail server
> sendmail.example.com. But about 50% of spam messages arrive directly
> to sendmail server, I guess that is because DNS A record points to it
> (web-site example.com resides on the same server where sendmail is
> installed)
>
> How can I configure sendmail in such a way, that it accepts mails for
> @example.com from 11.11.11.11 only?
> Btw, sendmail is providing service for other mail domains, which
> should not be affected by this filter, so I cannot simply close smtp
> connections not from 11.11.11.11 in firewall.
>
> I tried to add this lines to /etc/access :
> To:example.com 441 Please use our MX server
> 11.11.11.11 RELAY
>
> But mail from 11.11.11.11 is always blocked by check_rcpt rule.
>
> Thanks in advance.



Here is the simplistic way to do this in the access file. There are
more complex ways,

Connect:11.11.11.11 OK
Connect:1 550 Please use the MX server or contact
support
Connect:2 550 Please use the MX server or contact
support
...
...
Connect:256 550 Please use the MX server or contact
support