메일로그화일분석하는법 좀 알려주세요

메일로그화일 보면

May  3 17:34:15 localhost sendmail[22529]: i438Y0Zg022529: i438Y0Zh022529: return to sender: User unknown
May  3 17:34:15 localhost sendmail[22529]: i438Y0Zh022529: to=root, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=32941, dsn=2.0.0, stat=Sent
May  3 17:34:28 localhost sendmail[22332]: i438Qxa9020039: to=<sharonhardy@hotmail.com>, delay=00:01:12, xdelay=00:01:07, mailer=esmtp, pri=30220, relay=mx3.hotmail.com. [64.4.50.239], dsn=2.0.0, stat=Sent ( <200405030833.i438Qxa9020039@localhost.localdomain> Queued mail for delivery)
May  3 17:34:58 localhost sendmail[22477]: i438YBZg022477: to=<teacheradministrable@ntlworld.com>, delay=00:00:47, xdelay=00:00:47, mailer=esmtp, pri=31988, relay=smtpin.ntlworld.com. [62.253.162.40], dsn=5.1.1, stat=User unknown
May  3 17:34:58 localhost sendmail[22477]: i438YBZg022477: i438YBZh022477: return to sender: User unknown
May  3 17:34:58 localhost sendmail[22477]: i438YBZh022477: to=root, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=33012, dsn=2.0.0, stat=Sent
May  3 17:35:31 localhost sendmail[22351]: i438XgZg022351: to=<counseloreuropium@swbell.net>, delay=00:01:49, xdelay=00:01:49, mailer=esmtp, pri=31964, relay=sbcmail5.prodigy.net. [151.164.30.67], dsn=5.3.0, stat=User unknown
May  3 17:35:31 localhost sendmail[22351]: i438XgZg022351: i438XgZh022351: return to sender: User unknown
May  3 17:35:31 localhost sendmail[22351]: i438XgZh022351: to=root, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=32988, dsn=2.0.0, stat=Sent
May  3 17:35:38 localhost sendmail[30336]: i430vxtb010661: to=<aegm.net@mg.nu>, delay=07:32:21, xdelay=00:02:00, mailer=esmtp, pri=660270, relay=mg.nu. [212.181.91.6], dsn=4.0.0, stat=Deferred: Connection timed out with mg.nu.
May  3 17:35:38 localhost sendmail[30336]: i4312UtC011871: to=<sawbellypounds@bellsouth.net>, delay=07:33:08, xdelay=00:00:00, mailer=esmtp, pri=661940, relay=mx00.mail.bellsouth.net., dsn=4.0.0, stat=Deferred: Name server: mx00.mail.bellsouth.net.: host name lookup failure
May  3 17:35:38 localhost sendmail[30336]: i43128tC011848: to=<portraitactively@bellsouth.net>, delay=07:33:30, xdelay=00:00:00, mailer=esmtp, pri=662046, relay=mx01.mail.bellsouth.net., dsn=4.0.0, stat=Deferred: Name server: mx01.mail.bellsouth.net.: host name lookup failure
May  3 17:37:40 localhost sendmail[14938]: i436bSZk017479: timeout waiting for input from mailin00.sul.t-online.de. during client greeting
May  3 17:38:47 localhost sendmail[30336]: i42LjdKa021009: to=<admin@stkd.net>, delay=10:51:33, xdelay=00:03:09, mailer=esmtp, pri=1110262, relay=stkd.net. [218.145.47.155], dsn=4.0.0, stat=Deferred: Name server: stkd.net.: host name lookup failure
May  3 17:39:01 localhost sendmail[24038]: i438cqZg024038: <digimon@comeda.com>... User unknown
May  3 17:39:01 localhost sendmail[24008]: i438d1Zg024008: [218.17.235.37] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
May  3 17:39:01 localhost sendmail[24038]: i438cqZg024038: lost input channel from [211.216.148.248] to MTA after rcpt
May  3 17:39:01 localhost sendmail[24038]: i438cqZg024038: from=<3piyrlemdp@hotmail.com>, size=0, class=0, nrcpts=0, proto=SMTP, daemon=MTA, relay=[211.216.148.248]
May  3 17:39:16 localhost sendmail[14938]: i436bSZk017479: to=<axet@t-online.de>, delay=02:01:19, xdelay=00:13:22, mailer=esmtp, pri=210262, relay=mailin06.sul.t-online.de. [194.25.134.11], dsn=2.0.0, stat=Sent (Message accepted.)
May  3 17:39:16 localhost sendmail[14938]: i4371HZg024937: to=<b_x@kiss.com>, delay=01:37:56, xdelay=00:00:00, mailer=esmtp, pri=210264, relay=kiss.com., dsn=4.0.0, stat=Deferred: Connection refused by kiss.com.

이렇게 쓰여있는데 relay는 뭘 나타내는것이고 pri,stat,dsn은 뭔지 궁금합니다.
그리구 메일이 서버에 들어오면 어디에서 온것인지 알수있는(이메일 주소가 아닌
보낸서버아이피나 도메인) 방법은 없는지 알려주시면 고맙겠습니다.