Основной домен abc-telecom.az

root@mail:~/Desktop# telnet mail.abc-telecom.az 25
Trying 62.217.135.242...
telnet: Unable to connect to remote host:
Connection refused
root@mail:~/Desktop#

Проверка с другого домена slovenia.az

root@mail:~/Desktop# telnet mail.slovenia.az 25
Trying 62.217.135.244...
Connected to mail.slovenia.az.
Escape character is '^]'.
220 abcmail.abc-telecom.az ESMTP Postfix (Ubuntu)