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Basj
Asked: 2017-09-01 15:39:10 +0800 CST

postfix still using ipv6 even if inet_protocols=ipv4

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I have set this in /etc/postfix/main.cf:

inet_protocols=ipv4 
#I also tried with smtp_address_preference=ipv4

But still, the received message in Gmail shows an IPV6 address next to SPF. Why?

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email

1 Answers

  1. The line you are looking at is not the whole story. The same message may result in travelling through both IPv4 and IPv6 as there might be more than one MTA-MTA connection. Therefore, you need to see the whole trace information, which Gmail shows on the same Original Message page.

    The SPF check is done against the last MTA before Gmail. You can compare Received-SPF header with the Received header above it: that's the MTA checked for SPF validity. Then look further and see the very first (in time i.e. last in order) Received header: there you can see the original connection from your Postfix. If inet_protocols=ipv4 was set and Postfix was restarted after the modification, there's no reason to believe that this is nothing but IPv4.

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