Sending email using an IP address instead of a domain name

Question

I try not to start the DNS servers in order to receive an email at the address on one of my virtual accounts.

I know that I can surround the IP address with square brackets, but how can I specify the mailbox username for the (virtual) hosted account on the server?

In other words,

• I have several domains hosted on a virtual server - everyone uses the same IP address.
• obviously [e-mail] works great
• but how can I send to user @ [123.456.78.90]

I want to do what is possible?

Thank.

Answer 1

The virtual host needs a domain name to figure out what to do. You want to send it to an IP address instead of a domain name. Thus, it will not work with conventional methods. You may be able to specify a default domain if none match. Otherwise, your only hope is to manually create an email. By this I mean:

telnet 123.456.78.9 25 HELO myhostname.mydomain MAIL From: <myemail@mydomain> RCPT To: <[e-mail]> DATA From: myemail@mydomain To: [e-mail] Subject: Testing This is a test . QUIT 

Answer 2

What you want to do is possible and even safe when using Cjdns IP addresses. Some clients (for example, mutt) are “broken” and throttled on raw ips as a domain. (While technically broken, this is an unusual use case - mutt is a good customer.)

You need to tell your MTA to accept the original ip. For example. in sendmail, add [123.456.78.9] / etc / mail / local -host-names

You also need to enable accept_unresolvable_domains , since sendmail does not seem to consider already resolved domains as "resolvable". (Other MTAs may require different settings).

I use thunderbird to send raw ips and it works fine. A friend uses claw mail without any problems.