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Topic: How to make outgoing mail prefer IPv6 connections?

I'm running a simple IRedMailEasy installation in LiNode.  They've assigned me an IPv4 address that's in a /24 block that once upon a time had an active spammer.  So about half the time, my IP is in a group that's blocked by UCEPROTECTL3.  Like anything @live.com, @outlook.com etc. 

If I could still have outgoing mail enabled on IPv4 but to prefer sending on IPv6, that would obviate the issue as that v6 block isn't tainted.

Thanks!

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Re: How to make outgoing mail prefer IPv6 connections?

Additional: I've added

smtp_address_preference=ipv6

to main.cf (via postconf -e smtp_address_preference=ipv6 in /opt/iredmail/custom/custom.sh)

But email sent to the hotmail server for example still delivers from the IPv4 address, thus bounces.

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Re: How to make outgoing mail prefer IPv6 connections?

you cant, UCE blocks the whole ASN, which aswell includes al ipv6 assaingments.

uceprotect should be avoided at ANY case

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Re: How to make outgoing mail prefer IPv6 connections?

What about using some SMTP Relay service? There's plenty of them out there, for example:
- Mailgun
- SendGrid
- Postmark
- SparkPost
- Sendinblue
- SMTP20GO
- and many many more....

The documentation to setup relay host on iRedMail can be found here: https://docs.iredmail.org/relayhost.html