Is IPV6 being demanded by Gmail?

1

I have been running MIAB with IPv6 disabled. I am now getting these errors. should I enable IPv6?

host
gmail-smtp-in.l.google.com[2607:f8b0:4023:1002::1b] said: 550-5.7.1
[2600:3c00::2000:98ff:fefa:77c] Gmail has detected that this message
550-5.7.1 does not meet IPv6 sending guidelines regarding PTR records and
550-5.7.1 authentication. For more information, go to 550 5.7.1
Email sender guidelines - Google Workspace Admin Help
46e09a7af769-7c6e31d1c93si851956a34.85 - gsmtp (in reply to end of DATA
command)

2

Are you sure? Gmail is explicitly mentioning an ipv6 address as the source, which should be yours. The ipv6 address should have a PTR.

3

MIAB should handle IPv6 and all the various bits and pieces out of the box. The only thing I’ve had to do was add a glue record, create a zone file for IPv6 reverse DNS delegation, tell my ISP to delegate to my name box :slight_smile:

I’ve not seen any reason to disable IPv6.

4

When I run System Status Checks, I get these messages about IPv6:

:heavy_multiplication_x: Incoming Mail (SMTP/postfix) is running and available over IPv4 but is not accessible over IPv6 at 2600:3c00::f03c:91ff:fe2e:1811 port 25.
:heavy_multiplication_x: Outgoing Mail (SMTP 465/postfix) is running and available over IPv4 but is not accessible over IPv6 at 2600:3c00::f03c:91ff:fe2e:1811 port 465.
:heavy_multiplication_x: Outgoing Mail (SMTP 587/postfix) is running and available over IPv4 but is not accessible over IPv6 at 2600:3c00::f03c:91ff:fe2e:1811 port 587.

what’s wrong?

5

FIXED! I had to change inet_protocols in /etc/postfix/main.cf to ‘all’ as it was set to IPv4.

6

Ok, so ipv6 is enabled and running. Now check that you have PTR set correctly for this ipv6 address.

7

Test results say that PTR is set correctly for both ipv4 & ipv6. mail to gmail is still being flagged as spam. I have put a google-site-verification TXT record in my DNS but google cannot find it even after 1-2 hours time.

8

I see 2600:3c00::f03c:91ff:fe2e:1811 indeed has PTR set, so that is good. But in the reject mail from google it says 2600:3c00::2000:98ff:fefa:77c which is different. And that last one does not have PTR set. Can you check you don´t have multiple IPv6 addresses bound to your box? Also check the content of /etc/mailinabox.conf

I see three TXT records containing google-site-verification on your domain. Maybe remove them all and only add one?

Final question: I see you modified the SPF record to include the IPv4 address of the box. Any reason for that? You are not trying to relay mail to another server correct? At any rate, there is a syntax error in there. The = in there should be a :

Even if this is all fixed, it might take google a while to allow your mails once more.