keepalive but no ping in tcpdump

[stefan.poeter]

Hi everyone.

i've set up an openvpn access server and added a keepalive 10 120 directive the server config directive in the advanced settings. My understanding is, that the server now contacts the connected clients every 10 seconds and the client reconnect after a period of 120 seconds without a ping from the server.

So when I do a tcpdmp -i tun0 i should see those ping requests right? But I do not! Am I missing something?

Thanks for any help.

[novaflash]

No, you shouldn't see them. They're actions that occur in the OpenVPN protocol, and are like pings, but not transported outside of OpenVPN processes. Therefore not visible to tcpdump.

If you use tcpdump to monitor the transport packets for the VPN tunnel instead, you should see a regular blip of openvpn encrypted data come by, even if you are not sending any payload through.

[stefan.poeter]

That's it. When I monitored my network interface I saw the ACK coming from the OpenVPN Server every ten seconds. Thanks a lot.