Server keeps disconnecting clients every 5 minutes

Hi,

I've just noticed that my permanently connected clients seem to be 
disconnecting every 5 minutes on my pfSense 2.8.1 server. This is a 
section of a typical log for one user, filtering for lines containing 
"connected" and "exiting":

|Feb 17 17:53:38 pfSense openvpn[15564]: openvpn server 'ovpns1' user 
cert CN 'vlada' address '23.17.103.85:34179' - connected Feb 17 17:58:38 
pfSense openvpn[99922]: vlada/23.17.103.85:34179 Inactivity timeout 
(--inactive), exiting Feb 17 17:58:38 pfSense openvpn[73405]: openvpn 
server 'ovpns1' user cert CN 'vlada' address '23.17.103.85:34179' - 
disconnected Feb 17 17:59:31 pfSense openvpn[83599]: openvpn server 
'ovpns1' user cert CN 'vlada' address '23.17.103.85:51213' - connected 
Feb 17 18:04:31 pfSense openvpn[99922]: vlada/23.17.103.85:51213 
Inactivity timeout (--inactive), exiting Feb 17 18:04:31 pfSense 
openvpn[24171]: openvpn server 'ovpns1' user cert CN 'vlada' address 
'23.17.103.85:51213' - disconnected Feb 17 18:05:26 pfSense 
openvpn[58398]: openvpn server 'ovpns1' user cert CN 'vlada' address 
'23.17.103.85:41860' - connected Feb 17 18:10:25 pfSense openvpn[99922]: 
vlada/23.17.103.85:41860 Inactivity timeout (--inactive), exiting Feb 17 
18:10:25 pfSense openvpn[15154]: openvpn server 'ovpns1' user cert CN 
'vlada' address '23.17.103.85:41860' - disconnected Feb 17 18:11:18 
pfSense openvpn[51044]: openvpn server 'ovpns1' user cert CN 'vlada' 
address '23.17.103.85:44008' - connected Feb 17 18:16:17 pfSense 
openvpn[99922]: vlada/23.17.103.85:44008 Inactivity timeout 
(--inactive), exiting Feb 17 18:16:17 pfSense openvpn[5536]: openvpn 
server 'ovpns1' user cert CN 'vlada' address '23.17.103.85:44008' - 
disconnected Feb 17 18:17:13 pfSense openvpn[42663]: openvpn server 
'ovpns1' user cert CN 'vlada' address '23.17.103.85:59206' - connected 
Feb 17 18:22:12 pfSense openvpn[99922]: vlada/23.17.103.85:59206 
Inactivity timeout (--inactive), exiting Feb 17 18:22:12 pfSense 
openvpn[61870]: openvpn server 'ovpns1' user cert CN 'vlada' address 
'23.17.103.85:59206' - disconnected |

In my server config I have a couple of lines:

|keepalive 10 60 inactive 300 |

As far as I understand the keepalive automatically gets pushed to the 
clients as well, so there should be keepalive pings from both ends every 
10s, therefore the inactive timeout of 300s should never be hit, but 
this does not appear to be the case.

In troubleshooting, I've tried setting keepalive to 0 in the UI and this 
disables the setting. This works and stops the disconnects, but I 
believe is undesirable.

I have then set the keepalive back to 300s, but set up a single ping to 
each client, every 2 minutes in cron.d. This also stops the disconnects.

To me, I would then conclude that the OpenVPN keepalive setting is not 
working. Has anyone else seen this?

Using pfSense 2.8.1 with OpenVPN 2.6.14. Clients are Windows 10, Ubuntu 
24.04, Debian 12 and Raspbian.

Thanks,

Nick