Restricted tcp flow throughput in a VPN tunnel

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Restricted tcp flow throughput in a VPN tunnel

L1 Bithead

Hello all,
On my firewall I have a VPN tunnel dedicated to VEEAM backup copy to a remote site.
I have a throughput problem which is only present with TCP flows.
I don't have any QOS set on the interface of this tunnel. The flow rule is standard just to make allow.
The MTU is 1438 and the adjust tcp mss option is set to 40 for IPv4.
With UDP flows I have a throughput of 100M, with TCP flows I'm down to 10 - 15M.
How do I know what's restricting the throughput of my TCP flows so much?



Cyber Elite
Cyber Elite


Have you tried to 'Disable Server Response Inspection' on the security policies allowing the traffic? Could there be any asymmetric routing happening?


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