我有一個在 vultr 虛擬機器上運行的 SMTP 伺服器。我已將 rDNS 設定為指向我的郵件網域mail.idimitrov.dev。 DNS 設定指向 ipv4 和 ipv6 上的該機器，mail.idimitrov.dev並指向idimitrov.dev.
當我只向 gmail 發送電子郵件時，它告訴我沒有 PTR 記錄。
| host gmail-smtp-in.l.google.com [2a00:1450:4013:c07::1b]
| SMTP error from remote mail server after pipelined end of data:
| 550-5.7.25 [2001:19f0:6c01:2f25:399c:6832:fa7c:c123] The IP address sending this
| 550-5.7.25 message does not have a PTR record setup, or the corresponding
| 550-5.7.25 forward DNS entry does not point to the sending IP. As a policy,
| 550-5.7.25 Gmail does not accept messages from IPs with missing PTR records.
| 550-5.7.25 Please visit
| 550-5.7.25 https://support.google.com/mail/answer/81126#ip-practices for more
| 550 5.7.25 information. fl6-20020a1709072a8600b008b466a03af6si17950149ejc.3 - gsmtp
其他郵件提供者的情況並非如此。
我更改了 rDNS 設定以指向idimitrov.dev並再次測試。相同的結果。
這是命令的輸出dig：
~ ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── at 08:55:53
❯ dig -x 209.250.239.243
; <<>> DiG 9.18.12 <<>> -x 209.250.239.243
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64879
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 96ded523f01fcbcb0100000063f70e07b977d3b949d3c8d8 (good)
;; QUESTION SECTION:
;243.239.250.209.in-addr.arpa. IN PTR
;; ANSWER SECTION:
243.239.250.209.in-addr.arpa. 3321 IN PTR idimitrov.dev.
;; Query time: 0 msec
;; SERVER: 192.168.0.1#53(192.168.0.1) (UDP)
;; WHEN: Thu Feb 23 08:56:07 EET 2023
;; MSG SIZE rcvd: 112
~ ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── at 08:56:07
❯ dig -x 2001:19f0:6c01:2f25:5400:04ff:fe48:12ba
; <<>> DiG 9.18.12 <<>> -x 2001:19f0:6c01:2f25:5400:04ff:fe48:12ba
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32491
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 82062aa836133bb70100000063f70e0a54a88c9478150aaa (good)
;; QUESTION SECTION:
;a.b.2.1.8.4.e.f.f.f.4.0.0.0.4.5.5.2.f.2.1.0.c.6.0.f.9.1.1.0.0.2.ip6.arpa. IN PTR
;; ANSWER SECTION:
a.b.2.1.8.4.e.f.f.f.4.0.0.0.4.5.5.2.f.2.1.0.c.6.0.f.9.1.1.0.0.2.ip6.arpa. 3445 IN PTR idimitrov.dev.
;; Query time: 0 msec
;; SERVER: 192.168.0.1#53(192.168.0.1) (UDP)
;; WHEN: Thu Feb 23 08:56:10 EET 2023
;; MSG SIZE rcvd: 156
它顯示我已經為 ipv4 和 ipv6 設定了 rDNS。
為什麼谷歌不這麼說？