更新：可以通过在 docker 容器内安装 Postfix 来重现此问题。
我尝试从源 2.x 和 3.x 重新编译最新的 Postfix 版本，但是并没有解决问题。
我已经配置了 Postfix 来发送和接收电子邮件，但是存在硬退回电子邮件的问题 - 它们不会被拒绝，并且 Postfix 每隔 x 分钟重复发送一次，并且用户多次收到“未送达的邮件退回给发件人”。
在 mail.log 中我看到：[..] delay=5.2, delays=0.11/0.01/0.07/5, dsn=4.3.0, status=deferred (bounce or trace service failure)
我-v在 master.cf 中添加了 bounce、qmgr 守护进程，但仍然不知道哪里出了问题。
这是我的配置：
# postconf -nf:
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
inet_interfaces = all
inet_protocols = all
local_recipient_maps = $virtual_mailbox_maps
mailbox_size_limit = 0
message_size_limit = 134217728
milter_default_action = accept
mydestination = localhost
myhostname = box.example.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
non_smtpd_milters = $smtpd_milters
notify_classes = bounce, delay, resource, software
readme_directory = no
recipient_delimiter = +
smtp_dns_support_level = dnssec
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_tls_loglevel = 2
smtp_tls_security_level = dane
smtpd_banner = ESMTP $mail_name
smtpd_milters = inet:127.0.0.1:8891 inet:127.0.0.1:8893
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks,
reject_rbl_client zen.spamhaus.org, reject_unlisted_recipient,
check_policy_service inet:127.0.0.1:10023
smtpd_relay_restrictions =
permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = pgsql:/etc/postfix/pgsql/sender-login-maps.cf
smtpd_sender_restrictions = reject_non_fqdn_sender,
reject_unknown_sender_domain, reject_authenticated_sender_login_mismatch,
reject_rhsbl_sender dbl.spamhaus.org
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/nginx/ssl/example.crt
smtpd_tls_ciphers = medium
smtpd_tls_dh1024_param_file = /etc/nginx/ssl/dh2048.pem
smtpd_tls_exclude_ciphers = aNULL
smtpd_tls_key_file = /etc/nginx/ssl/example.key
smtpd_tls_received_header = yes
smtpd_tls_security_level = may
smtpd_use_tls = yes
soft_bounce = no
virtual_alias_maps = pgsql:/etc/postfix/pgsql/virtual_alias_maps.cf
virtual_gid_maps = static:5000
virtual_mailbox_domains = pgsql:/etc/postfix/pgsql/virtual_domains_maps.cf
virtual_mailbox_maps = pgsql:/etc/postfix/pgsql/virtual_mailbox_maps.cf
virtual_transport = lmtp:[127.0.0.1]:10026
virtual_uid_maps = static:5000
# postconf -Mf
smtp inet n - - - - smtpd
submission inet n - - - - smtpd
-o content_filter=
-o syslog_name=postfix/submission
-o smtpd_milters=inet:127.0.0.1:8891
-o smtpd_tls_security_level=encrypt
-o smtpd_tls_ciphers=high
-o smtpd_tls_exclude_ciphers=aNULL,DES,3DES,MD5,DES+MD5,RC4
-o smtpd_tls_mandatory_protocols=!SSLv2,!SSLv3
-o cleanup_service_name=authclean
authclean unix n - - - 0 cleanup
-o header_checks=regexp:/etc/postfix/header_checks
pickup unix n - - 60 1 pickup
-o content_filter=
-o receive_override_options=no_header_body_checks
cleanup unix n - - - 0 cleanup
qmgr unix n - n 300 1 qmgr
tlsmgr unix - - - 1000? 1 tlsmgr
rewrite unix - - - - - trivial-rewrite
bounce unix - - - - 0 bounce
defer unix - - - - 0 bounce
trace unix - - - - 0 bounce
verify unix - - - - 1 verify
flush unix n - - 1000? 0 flush
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap
smtp unix - - - - - smtp
relay unix - - - - - smtp
showq unix n - - - - showq
error unix - - - - - error
retry unix - - - - - error
discard unix - - - - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - - - - lmtp
anvil unix - - - - 1 anvil
scache unix - - - - 1 scache
maildrop unix - n n - - pipe flags=DRhu
user=vmail argv=/usr/bin/maildrop -d ${recipient}
uucp unix - n n - - pipe flags=Fqhu
user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
ifmail unix - n n - - pipe flags=F user=ftn
argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp unix - n n - - pipe flags=Fq.
user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n n - 2 pipe flags=R
user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop}
${user} ${extension}
mailman unix - n n - - pipe flags=FR
user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py ${nexthop}
${user}
smtp-amavis unix - - - - 2 smtp
-o smtp_data_done_timeout=1200
-o smtp_send_xforward_command=yes
-o disable_dns_lookups=yes
-o max_use=20
127.0.0.1:10025 inet n - - - - smtpd
-o content_filter=
-o local_recipient_maps=
-o relay_recipient_maps=
-o smtpd_restriction_classes=
-o smtpd_delay_reject=no
-o smtpd_client_restrictions=permit_mynetworks,reject
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o smtpd_data_restrictions=reject_unauth_pipelining
-o smtpd_end_of_data_restrictions=
-o mynetworks=127.0.0.0/8
-o smtpd_error_sleep_time=0
-o smtpd_soft_error_limit=1001
-o smtpd_hard_error_limit=1000
-o smtpd_client_connection_count_limit=0
-o smtpd_client_connection_rate_limit=0
-o receive_override_options=no_header_body_checks,no_unknown_recipient_checks,no_milters
和我的邮件日志：
Jul 31 08:19:49 b1037ca901c1 postfix/submission/smtpd[22107]: connect from localhost[127.0.0.1]
Jul 31 08:19:49 b1037ca901c1 postfix/submission/smtpd[22107]: CCAF8D80222: client=localhost[127.0.0.1], sasl_method=LOGIN, [email protected]
Jul 31 08:19:49 b1037ca901c1 postfix/cleanup[22109]: CCAF8D80222: replace: header Received: from box.example.com (localhost [127.0.0.1])??(using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits))??(No client certificate requested)??by box.example.com (Postfix) with ESMTPSA id CCAF8D802 from localhost[127.0.0.1]; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<box.example.com>: Received: from authenticated-user (unknown [127.0.0.1])??(using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits))??(No client certificate requested)??by box.example.com (Postfix) with ESMTPSA id CCAF8D80222??for <[email protected]>; Fri, 31 Jul 2015 08:19:49 +0000 (UTC)
Jul 31 08:19:49 b1037ca901c1 postfix/cleanup[22109]: CCAF8D80222: message-id=<[email protected]>
Jul 31 08:19:49 b1037ca901c1 postfix/qmgr[20607]: CCAF8D80222: from=<[email protected]>, size=646, nrcpt=1 (queue active)
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: setting up TLS connection to smtp1.toexample.com[23.75.25.14]:25
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: smtp1.toexample.com[23.75.25.14]:25: TLS cipher list "aNULL:-aNULL:ALL:+RC4:@STRENGTH"
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:before/connect initialization
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:unknown state
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 read server hello A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: smtp1.toexample.com[23.75.25.14]:25: depth=0 verify=0 subject=/C=LV/O=EXample/OU=ITC/CN=smtp1.toexample.com
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: smtp1.toexample.com[23.75.25.14]:25: depth=0 verify=0 subject=/C=LV/O=EXample/OU=ITC/CN=smtp1.toexample.com
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 read server certificate A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 read server certificate request A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 read server done A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 write client certificate A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 write client key exchange A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 write change cipher spec A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 write finished A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 flush data
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: SSL_connect:SSLv3 read finished A
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: smtp1.toexample.com[23.75.25.14]:25: subject_CN=smtp1.toexample.com, issuer_CN=smtp1.toexample.com, fingerprint=F1:6E:B7:64:96:D3:DB:5C:F6:7D:37:89:BE:5D:E8:74, pkey_fingerprint=A8:F4:72:BA:D8:16:26:11:67:F5:10:4F:96:C3:CF:29
Jul 31 08:19:49 b1037ca901c1 postfix/smtp[22110]: Untrusted TLS connection established to smtp1.toexample.com[23.75.25.14]:25: TLSv1 with cipher AES128-SHA (128/128 bits)
Jul 31 08:19:50 b1037ca901c1 postfix/submission/smtpd[22107]: disconnect from localhost[127.0.0.1]
Jul 31 08:19:55 b1037ca901c1 postfix/smtp[22110]: CCAF8D80222: to=<[email protected]>, relay=smtp1.toexample.com[23.75.25.14]:25, delay=5.2, delays=0.08/0/0.07/5, dsn=4.3.0, status=deferred (bounce or trace service failure)
并且以下是退回的电子邮件（一封发给用户，一封发给邮政局长）
Jul 31 08:20:05 b1037ca901c1 postfix/cleanup[22139]: 068B1D80225: message-id=<[email protected]>
Jul 31 08:20:05 b1037ca901c1 postfix/bounce[22138]: CCAF8D80222: sender non-delivery notification: 068B1D80225
Jul 31 08:20:05 b1037ca901c1 postfix/qmgr[20607]: 068B1D80225: from=<>, size=2934, nrcpt=1 (queue active)
Jul 31 08:20:05 b1037ca901c1 postfix/cleanup[22139]: 090D2D80226: message-id=<[email protected]>
Jul 31 08:20:05 b1037ca901c1 postfix/bounce[22138]: CCAF8D80222: postmaster non-delivery notification: 090D2D80226
Jul 31 08:20:05 b1037ca901c1 postfix/qmgr[20607]: 090D2D80226: from=<[email protected]>, size=2536, nrcpt=1 (queue active)
Jul 31 08:20:05 b1037ca901c1 postfix/qmgr[20607]: CCAF8D80222: status=deferred (bounce failed)
Jul 31 08:20:05 b1037ca901c1 postfix/lmtp[22140]: 068B1D80225: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10026, delay=0.03, delays=0.02/0/0/0.01, dsn=2.0.0, status=sent (250 2.0.0 <[email protected]> kdV1ArUvu1V+VgAADqs49A Saved)
Jul 31 08:20:05 b1037ca901c1 postfix/qmgr[20607]: 068B1D80225: removed
Jul 31 08:20:05 b1037ca901c1 postfix/lmtp[22141]: 090D2D80226: to=<[email protected]>, orig_to=<postmaster>, relay=127.0.0.1[127.0.0.1]:10026, delay=0.01, delays=0/0/0/0.01, dsn=2.0.0, status=sent (250 2.0.0 <[email protected]> 4tOQArUvu1V/VgAADqs49A Saved)
Jul 31 08:20:05 b1037ca901c1 postfix/qmgr[20607]: 090D2D80226: removed
以下是完整详细日志：http://pastebin.com/bsFDsFB9（将其编辑到问题中会使问题太长 - MadHatter）。
我的配置可能有问题，或者 Postfix 2.11.0 中有错误？
答案1
该问题与 docker + postfix + Ubuntu 14.04.3 LTS 内核为 3.16 的主机有关（我没有使用 3.13 进行测试）。
如果在 docker 容器内安装了 postfix，则无需更改任何配置即可重现问题。
我尝试从源代码（2.x 和 3.x）重建 postfix，但是并没有解决问题。
为了解决这个问题，我必须安装适用于 Ubuntu LTS 的最新内核版本 - 3.19。apt-get install linux-generic-lts-vivid
答案2
我在使用 LXC 时也遇到了类似的问题。就我而言，将内核升级到最新可用版本 3.19.0-39 并没有解决问题。
我发现了与此问题相关的错误报告：https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1446906
Docker 使用 LXC 容器，因此这与之相关。在纯 LXC 中，可以通过使用 ( lxc.aa_profile = unconfined) 关闭 apparmor 配置文件来临时修复此问题。在 docker 中，可以使用--lxc-conf命令键传递 LXC 选项。