On 11/19/21 14:53, russellbell--- via Exim-users wrote:
> I'm trying to configure a domain that has never accepted mail
> from external sources to start. The server runs exim, which I've
> never used. I send a message to the domain using its IP, for example
> fred@123.456.789.012.
That is not normally done.
Email addresses have two parts: localpart @ domain. The domain is usually a domain.
If you want to use an IP address it would normally be fred@??? - the IP address goes in square brackets.
You can configure exim to accept mail sent to a particular IP address and translate that to a domain but I can only guess you don't really want to go through that trouble.
> exim returns:
>
> 'rejected RCPT : The mail server could not deliver mail to
> 'fred@123.456.789.012. The account or domain may not exist,
> 'they may be blacklisted, or missing the proper dns entries.'
We would of course need to see your exim configuration and relevant lines from your log files to understand exactly what happened, but in either case that doesn't matter because you're not doing this the right way,
> dig mx 123.456.789.012
IP addresses are not domain names. They can not have MX records.
>
> returns NXDOMAIN.
>
> fred gets and sends mail locally (sends it to remote
> addressees too), is not in the blacklist; 123.456.789.012 is a valid IP.
> Why does the message get to exim if the MX domain doesn't
> exist?
You haven't explained how the email was sent. Something contacted your exim. What was it?
But perhaps something decided that 123.456.789.012 is an IP address even though it wasn't in [ ] and attempted direct delivery.
It would be very likely to do so if you used a domain name. If there is any domain name that has an A record pointing to 123.456.789.012, it is likely to work much more often than using the IP address directly, even if it has no MX record.
> Since it gets to exim, is it possible to get exim to ignore
> the lack of a DNS entry for the domain and send fred the message?
Is fred a local user?
It would be a matter of setting up 123.456.789.012 as a local domain.
Again, if there is any DNS *name* that *points* to this server it would be a far more conventional setup.
SMTP servers will often try to find an A record, as a fallback, if no MX record exists.
