There is a VPS. It has Exim installed with the standard configuration. Registered MX record mail.source.ru . MTA works and sends messages via:

 mail -s "Example subject" -r from@source.ru to@target.ru

But when connected via telnet:

 telnet localhost 25

and recruitment:

 > HELO source.ru > mail from: from@source.ru > rcpt to: to@target.ru < 451 temporary local problem

the message is not sent and there is an error in the logs:

 temporarily rejected RCPT to@target.ru: Could not complete sender verify

Perhaps the reason is the misuse of telnet . How then to use / configure it correctly?

    1 answer 1

    The solution was as follows. Register in /etc/exim/exim.conf :

     domainlist relay_to_domains = source.ru

    After the message from info@source.ru start to be sent, and from some abc@source.ru an error is received:

     550-Verification failed for <abc@source.ru> 550-Unknown user 550-Sender verify failed

    Add to the /etc/aliases file:

     abc: postmaster

    Thus, the forwarding for pseudo-accounts begins to work. The question is why this is necessary when sending messages remains open.