DKIM 密钥无效 - RSA 签名错误

Question

我使用 opendkim 和 postfix 在 Ubuntu 14.04 机器上安装了 DKIM。我生成了 RSA 密钥对并更新了 TXT 记录。

在 www.mail-tester.com or www.dkimvalidator.com 等任何 DKIM 测试仪上测试设置时，出现 "result = fail, bad RSA signature" 等错误。

这是一个示例邮件（来自 dkimvalidator.com 的信息）。我用 mail.example.com.

替换了真实域

DKIM Signature


Message contains this DKIM Signature:
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mail.example.com;
     h=content-type:content-type:mime-version:subject:subject
    :message-id:to:reply-to:from:from; s=dkim; t=1505761379; x=
    1506625380; bh=xp3gKk5P39UaB7IV9Rj58h82gFaIiEDAqCbmUtWe2Yo=; b=s
    ErbZFhFhPQjrOz2dH2RlYMAaN0oUKT7SBJe/bQg5Uxq86VHr7HkHRnnqtw1lkRL6
    Ha6Qd2rXAV+ftc5vL3K3TYojBz8HFigZtmJetjgY1/evk9XnRHtTaRBD6/ZrXtii
    Rsa87O6RsoM7om9brPP8QW01/84nPSonJIIQtobLt0=


Signature Information:
v= Version:         1
a= Algorithm:       rsa-sha256
c= Method:          relaxed/simple
d= Domain:          mail.example.com
s= Selector:        dkim
q= Protocol:        
bh=                 xp3gKk5P39UaB7IV9Rj58h82gFaIiEDAqCbmUtWe2Yo=
h= Signed Headers:  content-type:content-type:mime-version:subject:subject
    :message-id:to:reply-to:from:from
b= Data:            s
    ErbZFhFhPQjrOz2dH2RlYMAaN0oUKT7SBJe/bQg5Uxq86VHr7HkHRnnqtw1lkRL6
    Ha6Qd2rXAV+ftc5vL3K3TYojBz8HFigZtmJetjgY1/evk9XnRHtTaRBD6/ZrXtii
    Rsa87O6RsoM7om9brPP8QW01/84nPSonJIIQtobLt0=
Public Key DNS Lookup


Building DNS Query for dkim._domainkey.mail.example.com
Retrieved this publickey from DNS: v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDIbe1WBW7hf4IbeW8acNXKzi6uQb2UXagkJoLWqGqLaXbnrLmwEjgxzoJQRR7iLq4/niGmI76Nzbc0aASTGYRdAK62/Enjove3W70vl92VSgGy1Tm0oZ+9/4+Z8qLiwikPs+HL961CshehcAMu1aLnVSyMwe77pOlf6ZPG7Lxj5QIDAQAB
Validating Signature


result = fail
Details: bad RSA signature

这里是 /etc/opendimk.conf：

# Log to syslog
Syslog                  yes
# Required to use local socket with MTAs that access the socket as a non-
# privileged user (e.g. Postfix)
UMask                   002

Domain                  mail.example.com
KeyFile                 /etc/dkimkeys/dkim.key
Selector                dkim

# Commonly-used options; the commented-out versions show the defaults.
#Canonicalization       simple
#Mode                   sv
#SubDomains             no


OversignHeaders         From

TrustAnchorFile       /usr/share/dns/root.key

会不会因为我使用像 johndoe@mail.example.com 这样的子域来发送电子邮件而出现问题？

Answer 1

问题是因为 opendkim 没有监听指定的套接字； Postfix 无法访问 opendkim，因此电子邮件未签名。

相关：https://serverfault.com/questions/847435/cant-change-opendkim-socket-in-debian-stretch-in-etc-default-opendkim

DKIM 密钥无效 - RSA 签名错误

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