我们的后缀有时会拒绝电子邮件。 我在我们的后缀日志（/var/log/mail.log）中看到这个错误：
Feb 9 16:16:33 sd-15xxx postfix/smtpd[1972]: NOQUEUE: reject: RCPT from unknown[xxxx]: 450 4.7.1 Client host rejected: cannot find your hostname, [xxxx]; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<smtp.sender.com> 这是我的postconf -n：
append_dot_mydomain = yes biff = no config_directory = /etc/postfix disable_vrfy_command = yes inet_interfaces = all mydestination = localhost, localhost.localdomain, sd-15xxx.dedibox.fr mydomain = my-domain.com myhostname = my-domain.com mynetworks = 127.0.0.0/8 192.168.0.0/24 yyyy <our server IP address> relayhost = smtpd_banner = $myhostname ESMTP (Debian/GNU) smtpd_client_restrictions = reject_unknown_client, permit_mynetworks smtpd_helo_required = yes smtpd_recipient_restrictions = permit_mynetworks, reject_unauth_destination, reject_unknown_recipient_domain, reject_non_fqdn_recipient smtpd_sender_restrictions = permit_mynetworks, reject_unknown_sender_domain, warn_if_reject reject_unverified_sender virtual_alias_maps = mysql:/etc/postfix/mysql-virtual_aliases.cf,mysql:/etc/postfix/mysql-virtual_aliases_mailbox.cf virtual_gid_maps = static:5000 virtual_mailbox_base = /var/spool/vmail/ virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual_domains.cf virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual_mailboxes.cf virtual_uid_maps = static:5000
这不是经常发生，但如果我们错过了一个重要的电子邮件，它可能会有严重的后果。
你看到这个问题来自哪里？ 这是一个configuration问题或反向DNS问题（当我读的地方）？
这是nslookup xxxx的结果：
41.180.106.89.in-addr.arpa name = Smtp16.sender.com. Authoritative answers can be found from: 180.106.89.in-addr.arpa nameserver = dns2.iland.com. 180.106.89.in-addr.arpa nameserver = dns3.iland.com. 180.106.89.in-addr.arpa nameserver = dns1.iland.com. dns1.iland.com internet address = 65.57.248.5 dns2.iland.com internet address = 63.211.182.4 dns3.iland.com internet address = 64.154.20.10
和挖的结果xxxx：
; <<>> DiG 9.5.1-P3 <<>> xxxx ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 5920 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;xxxx IN A ;; AUTHORITY SECTION: . 10800 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2010020901 1800 900 604800 86400 ;; Query time: 227 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Wed Feb 10 13:45:54 2010 ;; MSG SIZE rcvd: 106
我甚至不知道问题是从我们这边还是从发送方来的。
这是由reject_unknown_client指令引起的（ http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname ）
这是因为发送电子邮件的IP地址（您的情况为xxxx）没有返回有效的反向DNS条目 – 要么是因为在名称服务器上没有提供有效主机名的ptrlogging，要么是因为您的dns查找失败。 首先要尝试的是'nslookup xxxx'来看看你得到了什么。