[Bug 1549388] [NEW] In some rare cases Postfix connect to a wrong MX server

[Msd]

Public bug reported:

Hi,

I see on the logs of some of my server some strange lines :

Jan 27 11:39:53 v07 postfix/smtp[11468]: 9CCE614ED3E: to=<XXX at yahoo.fr>,
relay=gmail-smtp-in.l.google.com[64.233.184.26]:25, conn_use=2,
delay=8.2, delays=0.11/7.9/0.01/0.21, dsn=5.1.1, status=bounced (host
gmail-smtp-in.l.google.com[64.233.184.26] said: 550-5.1.1 The email
account that you tried to reach does not exist. Please try 550-5.1.1
double-checking the recipient's email address for typos or 550-5.1.1
unnecessary spaces. Learn more at 550 5.1.1
https://support.google.com/mail/answer/6596 h127si11333632wmd.92 - gsmtp
(in reply to RCPT TO command))

Here you can see a mail to a yahoo.fr domain and postfix tries to
deliver the mail to gmail-smtp-in.l.google.com !

And there is another strange thing : "conn_use=2". Normally, when
Postfix uses TLS, he can't reuse a connection and with Gmail, Postfix
has to use TLS...

So I look in the smtp process log "11468", just before my line :

Jan 27 11:39:51 v07 postfix/smtp[11468]: SSL_connect error to gmail-smtp-in.l.google.com[64.233.184.26]:25: lost connection
Jan 27 11:39:53 v07 postfix/smtp[11468]: A747014ECAF: Cannot start TLS: handshake failure
Jan 27 11:39:53 v07 postfix/smtp[11468]: Host offered STARTTLS: [gmail-smtp-in.l.google.com]
Jan 27 11:39:53 v07 postfix/smtp[11468]: A747014ECAF: to=<YYY at gmail.com>, relay=gmail-smtp-in.l.google.com[64.233.184.26]:25, delay=19, delays=0.22/4.4/14/0.32, dsn=2.0.0, status=sent (250 2.0.0 OK 1453891193 h127si11333632wmd.92 - gsmtp)
Jan 27 11:39:53 v07 postfix/smtp[11468]: 9CCE614ED3E: to=<XXX at yahoo.fr>, relay=gmail-smtp-in.l.google.com[64.233.184.26]:25, conn_use=2, delay=8.2, delays=0.11/7.9/0.01/0.21, dsn=5.1.1, status=bounced (host gmail-smtp-in.l.google.com[64.233.184.26] said: 550-5.1.1 The email account that you tried to reach does not exist. Please try 550-5.1.1 double-checking the recipient's email address for typos or 550-5.1.1 unnecessary spaces. Learn more at 550 5.1.1  https://support.google.com/mail/answer/6596 h127si11333632wmd.92 - gsmtp (in reply to RCPT TO command))
Jan 27 11:39:54 v07 postfix/smtp[11468]: B8CD514ED41: to=<ZZZ at free.fr>, relay=mx1.free.fr[212.27.48.6]:25, conn_use=2, delay=8.3, delays=0.13/8/0.01/0.11, dsn=2.0.0, status=sent (250 OK)

In fact the TLS Handshake with gmail fails. It is why the connection is
not in TLS and why I see "conn_use".

I have a lot of examples like this if you need more (the to address is
not always yahoo.fr, sometimes it's outlook.com, aol.com, ...). Every
time I saw this bug, it is with gmail-smtp-in.l.google.com and there is
TLS Handshake bug.


Do you know what happens ?

** Affects: postfix (Ubuntu)
     Importance: Undecided
         Status: New

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Title:
  In some rare cases Postfix connect to a wrong MX server

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