场景:
这是一个生产邮件服务器,4年来,在大约50个域上有大约2000个邮箱,并且与几乎任何其他邮件服务器都能很好地工作。日志不断地被关注,下面的问题最近出现了。
Edit 1:UButntu16.04.6-后缀(3.1.0-3ubuntu0.3)
问题:
有一个邮件服务器似乎无法将邮件发送到此系统。
当4.7.25客户端主机被拒绝时,它会失败。
NOQUEUE: reject: RCPT from unknown[159.135.224.3]: 450 4.7.25 Client host rejected: cannot find your hostname, [159.135.224.3]
这就是我如何配置后缀,因为我希望避免中继没有反向dns记录。
root@mail:~# grep restrictions /etc/postfix/main.cf
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_rbl_client zen.spamhaus.org, check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf, check_recipient_access mysql:/etc/postfix/mysql-virtual_policy_greylist.cf, check_policy_service unix:private/policy-spf
smtpd_helo_restrictions = permit_sasl_authenticated, permit_mynetworks, check_helo_access regexp:/etc/postfix/helo_access, reject_invalid_hostname, reject_non_fqdn_hostname, reject_invalid_helo_hostname, reject_unknown_helo_hostname, check_helo_access regexp:/etc/postfix/blacklist_helo
smtpd_sender_restrictions = check_sender_access regexp:/etc/postfix/tag_as_originating.re , permit_mynetworks, permit_sasl_authenticated, check_sender_access mysql:/etc/postfix/mysql-virtual_sender.cf, check_sender_access regexp:/etc/postfix/tag_as_foreign.re, reject_unknown_sender_domain, reject_unknown_reverse_client_hostname, check_client_access hash:/etc/postfix/client_access, reject_unknown_client_hostname
smtpd_client_restrictions = check_client_access mysql:/etc/postfix/mysql-virtual_client.cf
但是它有一个有效的方法,在mailserver上本地测试exectued:
159.135.224.3DNS测试
root@mail:~# nslookup 159.135.224.3
Server: 1.1.1.1
Address: 1.1.1.1#53
Non-authoritative answer:
3.224.135.159.in-addr.arpa name = relay.teamgioia.it.
Authoritative answers can be found from:
root@mail:~# dig 159.135.224.3
; <<>> DiG 9.10.3-P4-Ubuntu <<>> 159.135.224.3
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 23656
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1452
;; QUESTION SECTION:
;159.135.224.3. IN A
;; AUTHORITY SECTION:
. 10165 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2019083000 1800 900 604800 86400
;; Query time: 6 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Fri Aug 30 12:18:21 CEST 2019
;; MSG SIZE rcvd: 117
<#>In解析器:
nameserver 1.1.1.1
nameserver 1.0.0.1
问题:
为什么reject_unknown_client_hostname
没有像我预期的那样工作呢?
如果这不是服务器的错误,而是发件人的错误,我如何白名单一些发件人,以避免他们的邮件被拒绝?
你也能解释或推测他们的错吗?
发布于 2019-08-30 12:48:23
IP地址与域查找不匹配。
引用文献资料的话:
当1)客户机IP地址->名称映射失败或名称->地址映射失败或<#>3)名称->地址映射与客户端IP地址不匹配时,拒绝请求。
如果查找客户端IP地址,则再次查找已解析的DNS名称,并比较这些名称:
$ nslookup 159.135.224.3
3.224.135.159.in-addr.arpa name = relay.teamgioia.it.
$ nslookup relay.teamgioia.it.
Non-authoritative answer:
relay.teamgioia.it canonical name = mailgun.org.
Name: mailgun.org
Address: 52.2.180.207
Name: mailgun.org
Address: 52.4.250.90
您可以看到,原始IP地址与DNS解析地址不匹配。这就是为什么它不能通过检查。
https://serverfault.com/questions/981289
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