1 Topic by Davesworld (edited by Davesworld 2026-08-17 01:42:30)

  • Davesworld
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  • Registered: 2013-04-15
  • Posts: 27

Topic: IPv6

Since I have both IPv4 and IPv6 working on my server now, I tried sending a test email from my Google account to see if the IPv6 address showed up. Looking at the mail log, it hung. The cause was the full IPv6 address under my networks =  line. After truncating it back to end at :: and reloading Postfix, the IPv6 mail came through. The subnet remains at /64 after the brackets.

Here is an abbreviated example of correct and incorrect:

Incorrect: [fd4d:6169:6c63::5]/64
Correct: [fd4d:6169:6c63::]/64

Shouldn't redeploying Postfix fix this in the future?

It would also be nice to be able to prefer IPv6 for SMTP, but of course have it completely controllable at a click. I added the line smtp_address_preference = ipv6 to be able to use IPv6  when the receiving server accepts it.

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2 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
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  • Registered: 2009-05-06
  • Posts: 31,754

Re: IPv6

Davesworld wrote:

Looking at the mail log, it hung.

What do you mean by "it hung"?
Please show me original Postfix log lines for troubleshooting.