Client behind Fortigate firewall

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Joined: Sat Mar 10, 2018 2:06 pm

Client behind Fortigate firewall

Post by niksa » Sat Mar 10, 2018 2:43 pm


I have a client which is behind a restrictive Fortigate firewall. I've had to use TCP over port 443 and it works, but the connection drops frequently. I thought that the Fortigate detects VPN traffic and drops it, but then I noticed that if I increase OpenVPN ping parameter to 3600, the connection remains up for an hour or so. So it must have something to do with OpenVPN keepalive mechanism, which I must admit I am puzzled with. For one thing, it is not clear from the manual if keepalive can be disabled, and what are the consequences (do I risk losing the connection permanently). Also, are ping attempts logged on either side? I can't see anything about it in the log. Alternatively, how do I capture just the ping packets with tcpdump?

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