WireGuard responses a Handshake Initiation packet with another Handshake Initiation instead of Handshake Response

[Silvan Nagl]

actually it was reproducible on my 4w old setup.
after updating both it ain't reproducible anymore.
openwrt: Quintus Build at 2021.05.23 / LuCI openwrt-21.02 branch 
git-21.136.64332-53c572a
fedora_server: 5.12.8-300.fc34.x86_64

On 03.06.2021 21:30, Silvan Nagl wrote:
> Reproducible:
>
> Client_a <-> Gateway_a <-> Internet <-> Server_b
>
> When Gateway_a changes its WAN-IP Client_a loses connection.
> Capture files show the state after the IP change.
>
> On 6/3/21 8:43 AM, Arınç ÜNAL wrote:
>> I tried wg syncconf wg0 <(wg-quick strip wg0) without success.
>>
>> Only restarting wireguard by systemctl restart wg-quick at wg0 makes it
>> respond with a Handshake Response packet.
>>
>> This happens really rarely and especially on OpenWrt 19.07 as a client.
>>
>> Other clients can handshake properly while the server fails to
>> complete the handshake for the OpenWrt device.
>>
>> Packet Captures on boths sides are in the attachments.
>>
>> Server:
>> 5.9.0-0.bpo.5-amd64 #1 SMP Debian 5.9.15-1~bpo10+1 (2020-12-31) x86_64 GNU/Linux
>> wireguard-tools v1.0.20210223 - https://git.zx2c4.com/wireguard-tools/
>> wireguard-dkms/buster-backports,now 1.0.20210219-1~bpo10+1
>>
>> Client:
>> 4.14.221 #0 SMP Mon Feb 15 15:22:37 2021 armv7l GNU/Linux
>> wireguard-tools v1.0.20191226 - https://git.zx2c4.com/wireguard-tools/
>> kmod-wireguard 4.14.221+1.0.20200611-2
>>
>> Arınç Ü.