При отправки почты с самого сервера другому пользователю или самому себе в /var/log/maillog пишется следующие
Aug 23 10:32:37 hkki sendmail[5837]: i7N2WVbF005835: to=<root@hkki.ru>, delay=00:00:06, xdelay=00:00:06, mailer=esmtp, pri=90385, relay=mail.ru.ru. [195.2.72.147], dsn=5.0.0, stat=Service unavailable Aug 23 10:32:37 hkki sendmail[5837]: i7N2WVbF005835: to=<adprox@hkki.ru>, delay=00:00:06, xdelay=00:00:06, mailer=esmtp, pri=90385, relay=mail.ru.ru. [195.2.72.147], dsn=5.0.0, stat=Service unavailable Aug 23 10:32:37 hkki sendmail[5837]: i7N2WVbF005835: to=<pavel@hkki.ru>, delay=00:00:06, xdelay=00:00:06, mailer=esmtp, pri=90385, relay=mail.ru.ru. [195.2.72.147], dsn=5.0.0, stat=Service unavailable Aug 23 10:32:37 hkki sendmail[5837]: i7N2WVbF005835: i7N2WbbF005837: DSN: Service unavailable Aug 23 10:32:37 hkki sendmail[5837]: i7N2WbbF005837: to=<root@hkki.ru>, delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=31434, relay=mail.ru.ru. [195.2.72.147], dsn=5.0.0, stat=Service unavailable Aug 23 10:32:38 hkki sendmail[5837]: i7N2WbbF005837: i7N2WbbG005837: return to sender: Service unavailable Aug 23 10:32:38 hkki sendmail[5837]: i7N2WbbG005837: to=root, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=32458, dsn=2.0.0, stat=Sent
