Domain-Name-System
451 #4.1.8 發件人地址的域未解析
當通過我自己的 SMTP 伺服器 (mail.sarit.be) 向 xxx@terremark.com 發送電子郵件時，接收郵件伺服器回复：
451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve從我的 postfix 日誌來看，所有接收的 MX 伺服器都無法解析 sarit.be 或 mail.sarit.be。
;; QUESTION SECTION: ;terremark.com. IN MX ;; ANSWER SECTION: terremark.com. 300 IN MX 15 fldsmtpe04.verizon.com. terremark.com. 300 IN MX 15 fldsmtpe01.verizon.com. terremark.com. 300 IN MX 15 fldsmtpe02.verizon.com. terremark.com. 300 IN MX 15 fldsmtpe03.verizon.com. Aug 6 08:47:42 charlie postfix/smtp[22257]: 2A45D2D56: to=<xxx@terremark.com>, relay=fldsmtpe01.verizon.com[140.108.26.140]:25, delay=418619, delays=418496/0.01/63/60, dsn=4.0.0, status=deferred (host fldsmtpe01.verizon.com[140.108.26.140] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)) Aug 6 09:56:41 charlie postfix/smtp[22866]: 2A45D2D56: host fldsmtpe02.verizon.com[140.108.26.141] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command) Aug 6 09:57:44 charlie postfix/smtp[22866]: 2A45D2D56: to=<xxx@terremark.com>, relay=fldsmtpe03.verizon.com[140.108.26.142]:25, delay=422821, delays=422697/0.01/64/60, dsn=4.0.0, status=deferred (host fldsmtpe03.verizon.com[140.108.26.142] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)) Aug 6 11:06:42 charlie postfix/smtp[23660]: 2A45D2D56: host fldsmtpe01.verizon.com[140.108.26.140] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command) Aug 6 11:07:44 charlie postfix/smtp[23660]: 2A45D2D56: to=<xxx@terremark.com>, relay=fldsmtpe03.verizon.com[140.108.26.142]:25, delay=427021, delays=426897/0.01/64/60, dsn=4.0.0, status=deferred (host fldsmtpe03.verizon.com[140.108.26.142] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)) Aug 6 12:16:42 charlie postfix/smtp[24312]: 2A45D2D56: host fldsmtpe04.verizon.com[140.108.26.143] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command) Aug 6 12:17:43 charlie postfix/smtp[24312]: 2A45D2D56: to=<xxx@terremark.com>, relay=fldsmtpe02.verizon.com[140.108.26.141]:25, delay=431221, delays=431097/0.01/63/60, dsn=4.0.0, status=deferred (host fldsmtpe02.verizon.com[140.108.26.141] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)) Aug 6 13:26:42 charlie postfix/smtp[24956]: 2A45D2D56: host fldsmtpe02.verizon.com[140.108.26.141] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command) Aug 6 13:27:43 charlie postfix/smtp[24956]: 2A45D2D56: to=<xxx@terremark.com>, relay=fldsmtpe04.verizon.com[140.108.26.143]:25, delay=435420, delays=435297/0.01/63/60, dsn=4.0.0, status=deferred (host fldsmtpe04.verizon.com[140.108.26.143] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)) Aug 8 08:21:34 charlie postfix/smtp[15495]: 46D6E6353: host fldsmtpe03.verizon.com[140.108.26.142] said: 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve (in reply to MAIL FROM command)我已經驗證了我的 MX 伺服器的反向 DNS 查找和 sarit.be 域的 SPF 記錄。
;; QUESTION SECTION: ;sarit.be. IN MX ;; ANSWER SECTION: sarit.be. 3600 IN MX 10 mail.sarit.be. ;; QUESTION SECTION: ;mail.sarit.be. IN A ;; ANSWER SECTION: mail.sarit.be. 2128 IN A 176.9.7.243 ;; QUESTION SECTION: ;243.7.9.176.in-addr.arpa. IN PTR ;; ANSWER SECTION: 243.7.9.176.in-addr.arpa. 43200 IN PTR mail.sarit.be. ;; QUESTION SECTION: ;sarit.be. IN SPF ;; ANSWER SECTION: sarit.be. 3600 IN SPF "v=spf1 +a +mx ~all"最後，我 tcpdump 了我自己的郵件伺服器和其他 MX 伺服器之間的 SMTP 流量：
220 fldsmtpe01.verizon.com ESMTP EHLO mail.sarit.be 250-fldsmtpe01.verizon.com 250-8BITMIME 250-SIZE 20971520 250 STARTTLS MAIL FROM:<xxx@sarit.be> SIZE=537 451 #4.1.8 Domain of sender address <xxx@sarit.be> does not resolve RSET 250 reset QUIT 221 fldsmtpe01.verizon.com我認為我的 DNS 內容沒有任何問題。我可以毫無問題地向其他域發送電子郵件。很容易認為錯誤出在接收郵件伺服器上。你怎麼看？
PS：在這種情況下，反向 DNS 的事情似乎並不那麼重要，因為當我從 xxx@telenet.be 向 xxx@terremark.com 發送郵件時，即使這些 MX 伺服器的正向/反向查找確實可以接受該電子郵件不匹配。
這看起來像是接收方的臨時 DNS 問題。他們的伺服器由於某種原因無法解析您的地址。我認為沒有什麼可以解決這個問題。可能您應該使用另一封電子郵件聯繫他們的代表，並要求他們解決這個問題。