Gmail - ipv6. Anyone else with this experience?

[joseph]

Can't think of a drawback of disabling IPv6 on the server. You should disable IPv6 on Cloudron side if this got auto-enabled Network -> IPv6 -> Diable. This way it won't configure AAAA records. You will have issues when installing new apps otherwise.

[avatar1024]

Right so we have a bunch of similar topics referencing the same problem.

• https://forum.cloudron.io/topic/13162/unable-to-send-emails-to-gmail
• https://forum.cloudron.io/topic/13145/problems-with-sending-mail
• https://forum.cloudron.io/topic/13122/email-sending-broken-after-updating-to-8-2-x-due-to-ipv6-issues
• https://forum.cloudron.io/topic/13072/gmail-ipv6-anyone-else-with-this-experience

Should they all be merged and/or marked as solved?

The solution is provided by @girish (here) and @jdaviescoates (here) which I'll compile and summarise here again:

1. Activate IPv6 on Cloudron via going to Network > IPv6 > Configure > Public IP
2. Check your IPv6 address either via reading the IPv6 address detected by Cloudron when doing 1. or via running curl https://ipv6.api.cloudron.io/api/v1/helper/public_ip on your server (via ssh).
3. Set an IPv6 PTR record on your VPS/server provider (not your domain provider) for the above IPv6 address. The next Cloudron release will implement a check on IPv6 PTR record like it currently does for IPv4.
4. If using Wildcard DNS then create a * AAAA record for the above IPv6 address.
5. If things still don't work, you can go to Cloudron -> Domains -> hit Sync DNS

If your VPS provider does not allow you to set IPv6 PTR, then disable IPv6 that way:

1. disable IPv6 in Cloudron (Network -> IPv6 -> Disable)
2. on your server via ssh run sysctl -w net.ipv6.conf.ens18.disable_ipv6=1 (replacing ens18 for your specific network interface, in my case eth0)
3. make it persistent by adding net.ipv6.conf.ens18.disable_ipv6=1 to /etc/sysctl.conf (replacing ens18 for your specific network interface, in my case eth0)

Update: I personally still faced issues with Gmail using IPv6 so I ended up disabling it persistently.