ERROR: I could not complete a connection to any of your mailservers!
istud.ru: Timed out [Last data sent: RCPT TO: ]
If this is a timeout problem, note that the DNS report only waits about 40 seconds for responses, so your mail *may* work fine in this case but you will need to use testing tools specifically designed for such situations to be certain.
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
exim4 2236 Debian-exim 4u IPv4 5015 TCP *:smtp (LISTEN)
exim4 27551 Debian-exim 5u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
exim4 27551 Debian-exim 6u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
lsof -i :25
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
exim4 2236 Debian-exim 4u IPv4 5015 TCP *:smtp (LISTEN)
exim4 27551 Debian-exim 5u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
exim4 27551 Debian-exim 6u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
lsof -i :25
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
exim4 2236 Debian-exim 4u IPv4 5015 TCP *:smtp (LISTEN)
exim4 27551 Debian-exim 5u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
exim4 27551 Debian-exim 6u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (ESTABLISHED)
lsof -i :25
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
exim4 2236 Debian-exim 4u IPv4 5015 TCP *:smtp (LISTEN)
exim4 27551 Debian-exim 5u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (CLOSE_WAIT)
exim4 27551 Debian-exim 6u IPv4 182475 TCP 85.249.72.106:smtp->test.DNSstuff.com:39507 (CLOSE_WAIT)