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What is safe for AAAA record. Short or full format?

I set this e.g.:

4a01:20:18:0:5:8:8:30

This is IP from mail server. But when smtp sending email out i see problems in logs. Gmail return email as spam and another server say that I have bad PTR. PTR is set correctly.

So, only one think is that correct format is

4a01:20:18::5:8:8:30

Which of these notations is correct?

Sander Steffann
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Pavel
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    Assuming those stars stand for digits, `18**` isn't the same as `18`, anyway; so you may have a bigger problem than just format. If you stop redacting your IP address it'll be a lot easier to help you. – MadHatter Jul 24 '14 at 09:09
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    I think you should go back and learn about IPV6. The safe format is irrelevant as they both are identical. Quite obviously the PRT is wrong message means this. Without full information we can not help. – TomTom Jul 24 '14 at 09:14
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    IPv6 addresses outside `2000::/3` have not been allocated for global unicast. The IPv6 address you mention can't be yours. Please show the real IP addresses. – Sander Steffann Jul 24 '14 at 09:28
  • @MadHatter stars was problem with bold formatting – Pavel Jul 24 '14 at 09:54
  • Can you run `dig +trace +add -x ipaddress` to validate that the `PTR` is actually in place and correct? – Håkan Lindqvist Jul 24 '14 at 10:53
  • @HåkanLindqvist ... PTR is returned ok. – Pavel Jul 24 '14 at 11:02
  • Can be problem, that IPv6 adr. was set only for primary domain in first moment? Other domains on mail server had only IPv4 as MX. – Pavel Jul 24 '14 at 11:04
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    Your `MX` records should not be a factor. What will matter is that the `PTR` can be looked up for the IP address you are connecting from and that the referenced name has an address record pointing back to that same IP address (forward-confirmed reverse dns). Ideally the name used here should also match the "mailname" (name used by your MTA in the smtp greeting, etc.). If all this checks out, have you changed any of this recently so that your tests may still be affected by old cached results? – Håkan Lindqvist Jul 24 '14 at 11:15
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    Also make sure that the server is making its outbound connection from the right address. It is very common and normal for a box to have multiple IPv6 addresses. If you didn't explicitly configure the address to use for outbound connection any address may be used. On mailservers you should always bind to a specific address for outbound connections. – Sander Steffann Jul 24 '14 at 12:42
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    `PTR is set correctly.` -- Show, don't tell. – Andrew B Jul 24 '14 at 13:14

1 Answers1

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Any valid IPv6 address notation according to RFC 4291 can be used for AAAA records. When working with IPv6 addresses it is usually best to stick to the recommended notation but it doesn't change anything. IPv6 addresses for AAAA records are transmitted in binary (see RFC3596) so the notation you use in your zone file has no impact on the transmitted data at all.

Community
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Sander Steffann
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  • this is correct to my question, thank you. but finally problem was in Icewarp Mail Server. There is IPv6 options, but after call on support, they say that IPv6 is very unstable :(. – Pavel Jul 27 '14 at 08:21
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    Sad to hear that such backwards products still exist :( – Sander Steffann Jul 27 '14 at 10:29