My first OpenVPN, ipv6 issues

[ozzo]

Hi all,

I'm configuring OpenVPN server on OPNSense, I already done it successfully on some linux machines some year back and now it is my first time on OPNSense.

Client connection hangs at:

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2024-09-05 22:26:14: Valid endpoint found: XX.XX.XX.XX:1194:udp
2024-09-05 22:26:14: TCP/UDP: Preserving recently used remote address: [AF_INET]XX.XX.XX.XX:1194
2024-09-05 22:26:14: UDPv4 link local (bound): [AF_INET][undef]:0
2024-09-05 22:26:14: UDPv4 link remote: [AF_INET]XX.XX.XX.XX:1194

In the OpenVPN log I see the following error repeated every few seconds:

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Connection Attempt write UDPv6: Can't assign requested address (fd=9,code=49)

It seems to be the same problem described here: https://www.reddit.com/r/OPNsenseFirewall/comments/1adzr5y/openvpn_setup_instances_getting_ipv6_address_error/
I tried to look for the setting to disable IPv6 in the Instance settings page but I can't find it.

What should I do?

[ozzo]

UPDATE: I was trying to test the connection from within the private network. I tried from outside, both smartphone and notebook connected flawlessly.

Not that it would be useful in any way (at least to me) but, out of curiosity, what should I change to make it work from the inside?

[oxivanisher]

I have the exact same problem. The connection is only not working from the inside and this is only happening since I switched from the legacy server setup to instances. Did you find out anything more?

UPDATE: I was trying to test the connection from within the private network. I tried from outside, both smartphone and notebook connected flawlessly.

Not that it would be useful in any way (at least to me) but, out of curiosity, what should I change to make it work from the inside?

[marigo]

Just use "UDP IPv4" protocol only; edit in your openvpn instance

[feld]

Something did change because it used to work just fine roaming the VPN between LTE/5G and my LAN. Even if you change it to "UDP IPv4" so those errors go away in the logs the connection gets established but traffic seems to fail to pass. It broke for me with OpenVPN and Wireguard at the same time.

It was working flawlessly in the past for several years...