The mail server built with postfix + Dovecot is processed as a transit server by Spam

I sent an email today, but failed to send it. Then I went to the server to check the log and found that the hard disk was filled with the cache queue and logs of spam,

Tail-F/var/log/maillog found the screen was flushed. Some logs are as follows:

Aug 17 09:39:01 www postfix/error[1173]: 455F050663: to=<[email protected]>, relay=none, delay=28778, delays=28631/146/0/0.51, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1229]: 296AE2FDCD: to=<[email protected]>, relay=none, delay=30507, delays=30360/147/0/0.21, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1138]: 1F9A853B47: to=<[email protected]>, relay=none, delay=28244, delays=28097/146/0/0.6, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1104]: B16DB3AB0B: to=<[email protected]>, relay=none, delay=29431, delays=29284/146/0/0.83, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1205]: B7F65597AE: to=<[email protected]>, relay=none, delay=26365, delays=26218/146/0/0.41, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1166]: 308EE43BD2: to=<[email protected]>, relay=none, delay=30716, delays=30569/147/0/0.06, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1140]: 9654E2B6A6: to=<[email protected]>, relay=none, delay=35359, delays=35213/146/0/0.79, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1134]: C74DA58B4C: to=<[email protected]>, relay=none, delay=26704, delays=26557/146/0/0.57, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)Aug 17 09:39:01 www postfix/error[1220]: 506172DC9A: to=<[email protected]>, relay=none, delay=34379, delays=34232/146/0/1.4, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with mx-tw.mail.gm0.yahoodns.net[203.188.197.119] while sending RCPT TO)

Let's take a look at the process and load of the system. The system is dizzy and the load is 28, so the server is not moving.

[[email protected] /]# toptop - 09:42:06 up 2 days, 22:13,  1 user,  load average: 28.81, 20.57, 12.43Tasks: 238 total,   1 running, 237 sleeping,   0 stopped,   0 zombieCpu(s):  4.4%us,  8.0%sy,  0.0%ni,  4.2%id, 82.7%wa,  0.5%hi,  0.2%si,  0.0%stMem:   3921316k total,  2927360k used,   993956k free,   520508k buffersSwap:        0k total,        0k used,        0k free,   671096k cached  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                  319 root      20   0 80764 3568 2656 S  3.7  0.1   0:13.37 master                                                                   323 postfix   20   0 80944 3568 2596 S  2.0  0.1   0:09.92 trivial-rewrite                                                          322 postfix   20   0  103m  28m 2712 D  1.7  0.7   0:09.09 qmgr                                                                     862 root      20   0  249m 4784 1032 S  1.7  0.1  14:18.73 rsyslogd                                                                 448 postfix   20   0 80984 3592 2596 S  1.0  0.1   0:03.35 trivial-rewrite                                                          255 root      20   0     0    0    0 D  0.7  0.0   5:59.75 jbd2/xvda1-8                                                             400 postfix   20   0 94400 5164 3588 S  0.7  0.1   0:00.21 smtpd                                                                   1293 root      20   0  761m 8096 2072 S  0.7  0.2   4:48.66 aegis_cli                                                               1877 postfix   20   0 80856 3528 2632 S  0.7  0.1   0:00.08 error                                                                   2024 postfix   20   0 80856 3536 2632 S  0.7  0.1   0:00.04 error                                                                   2152 postfix   20   0 80880 3492 2608 S  0.7  0.1   0:00.02 bounce                                                                  2158 postfix   20   0 80880 3496 2608 D  0.7  0.1   0:00.02 bounce                                                                  2162 root      20   0 15160 1428 1000 R  0.7  0.0   0:00.02 top                                                                      446 postfix   20   0 94400 5172 3604 S  0.3  0.1   0:00.18 smtpd                                                                    455 postfix   20   0 80988 3640 2712 S  0.3  0.1   0:00.10 cleanup                                                                  463 postfix   20   0 94400 5144 3576 S  0.3  0.1   0:00.16 smtpd                                                                    465 postfix   20   0 80988 3636 2712 S  0.3  0.1   0:00.10 cleanup                                                                 1018 postfix   20   0 80988 3640 2712 S  0.3  0.1   0:00.07 cleanup                                                                 1035 postfix   20   0 94400 5120 3548 S  0.3  0.1   0:00.09 smtpd                                                                   1040 postfix   20   0 94400 5140 3568 S  0.3  0.1   0:00.14 smtpd                                                                   1469 postfix   20   0 80856 3532 2632 S  0.3  0.1   0:00.22 error                                                                   1836 postfix   20   0 80856 3528 2632 S  0.3  0.1   0:00.09 error                                                                   1900 postfix   20   0 80856 3536 2632 S  0.3  0.1   0:00.06 error                                                                   1903 postfix   20   0 80856 3528 2632 S  0.3  0.1   0:00.06 error                                                                   1924 postfix   20   0 80856 3528 2632 S  0.3  0.1   0:00.06 error                                                                   1939 postfix   20   0 80856 3532 2632 S  0.3  0.1   0:00.05 error                                                                   1960 postfix   20   0 80856 3528 2632 S  0.3  0.1   0:00.05 error                                                                   1967 postfix   20   0 80856 3532 2632 S  0.3  0.1   0:00.05 error                                                                   1973 postfix   20   0 80856 3528 2632 S  0.3  0.1   0:00.05 error                                                                   1977 postfix   20   0 80856 3532 2632 S  0.3  0.1   0:00.04 error                                                                   2090 postfix   20   0 80880 3500 2608 D  0.3  0.1   0:00.01 bounce                                                                  2153 postfix   20   0 80880 3500 2608 D  0.3  0.1   0:00.01 bounce                                                                  2161 postfix   20   0 80880 3492 2608 D  0.3  0.1   0:00.01 bounce                                                                  2163 postfix   20   0 80880 3492 2608 D  0.3  0.1   0:00.01 bounce                                                                  2164 postfix   20   0 80880 3492 2608 D  0.3  0.1   0:00.01 bounce                                                                  2165 postfix   20   0 80880 3492 2608 D  0.3  0.1   0:00.01 bounce                                                                  2169 postfix   20   0 80880 3496 2608 D  0.3  0.1   0:00.01 bounce                                                                  2170 postfix   20   0 80880 3496 2608 D  0.3  0.1   0:00.01 bounce                                                                  2176 postfix   20   0 80880 3492 2608 D  0.3  0.1   0:00.01 bounce                                                                     1 root      20   0 19232 1088  820 S  0.0  0.0   0:00.87 init                                                                       2 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kthreadd                                                               

Stop the Postfix service and check the content of the forwarded spam:

[[email protected] /]# postcat -q 847D9E8238*** ENVELOPE RECORDS deferred/8/847D9E8238 ***message_size:            6545            3068              26               0            6545message_arrival_time: Sun Aug 17 10:15:10 2014create_time: Sun Aug 17 10:15:10 2014named_attribute: rewrite_context=remotesender: [email protected]named_attribute: log_client_name=36-224-134-61.dynamic-ip.hinet.netnamed_attribute: log_client_address=36.224.134.61named_attribute: log_client_port=2806named_attribute: log_message_origin=36-224-134-61.dynamic-ip.hinet.net[36.224.134.61]named_attribute: log_helo_name=115.28.81.191named_attribute: log_protocol_name=SMTPnamed_attribute: client_name=36-224-134-61.dynamic-ip.hinet.netnamed_attribute: reverse_client_name=36-224-134-61.dynamic-ip.hinet.netnamed_attribute: client_address=36.224.134.61named_attribute: client_port=2806named_attribute: helo_name=115.28.81.191named_attribute: protocol_name=SMTPnamed_attribute: client_address_type=2named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]named_attribute: dsn_orig_rcpt=rfc822;[email protected]original_recipient: [email protected]recipient: [email protected]*** MESSAGE CONTENTS deferred/8/847D9E8238 ***Received: from 115.28.81.191 (36-224-134-61.dynamic-ip.hinet.net [36.224.134.61])        by mail.sintie.com (Postfix) with SMTP id 847D9E8238;        Sun, 17 Aug 2014 10:15:10 +0800 (CST)Received: from 65.64.252.253 by ; Sun, 17 Aug 2014 06:09:08 +0400

Postfix is very powerful. You can set security authentication-related items to improve the security level.
After reconfiguration and authentication, check the log again:

Aug 17 10:52:49 www postfix/smtpd[5864]: NOQUEUE: reject: RCPT from 114-45-30-4.dynamic.hinet.net[114.45.30.4]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:49 www postfix/smtpd[5863]: NOQUEUE: reject: RCPT from 118-161-251-198.dynamic.hinet.net[118.161.251.198]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5865]: connect from 118-161-241-28.dynamic.hinet.net[118.161.241.28]Aug 17 10:52:50 www postfix/smtpd[5863]: NOQUEUE: reject: RCPT from 118-161-251-198.dynamic.hinet.net[118.161.251.198]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5864]: NOQUEUE: reject: RCPT from 114-45-30-4.dynamic.hinet.net[114.45.30.4]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5864]: NOQUEUE: reject: RCPT from 114-45-30-4.dynamic.hinet.net[114.45.30.4]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:50 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5859]: NOQUEUE: reject: RCPT from 114-45-30-4.dynamic.hinet.net[114.45.30.4]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5863]: NOQUEUE: reject: RCPT from 118-161-251-198.dynamic.hinet.net[118.161.251.198]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5864]: NOQUEUE: reject: RCPT from 114-45-30-4.dynamic.hinet.net[114.45.30.4]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>Aug 17 10:52:51 www postfix/smtpd[5865]: NOQUEUE: reject: RCPT from 118-161-241-28.dynamic.hinet.net[118.161.241.28]: 504 5.5.2 <115.28.81.191>: Helo command rejected: need fully-qualified hostname; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<115.28.81.191>

It was rejected by the server.

If you can analyze the log dynamically, put the IP address in the firewall and pass it directly.