IPSEC LAN to LAN Tunnel Slow One Way

[sc0ttjm]

Hi all,

I'm struggling a bit with a VPN between my site and a Data Center.

The VPN is rock solid but using iperf3 I can see that when a machine at the DC is acting as the iperf3 server, and a machine at the site is the client, we get a speed reading of around 8Mbps.

When we revers this and use the Data Center machine as a client, we get a speed reading of around 82Mbps.

I've tried changing MTU sizes but it doesn't seem to help.

Please could you help me get to the bottom of this?

Thanks

[sc0ttjm]

Just to provide a bit more updated info, I ran iperf3 on the host itself that has an LAN and a WAN interface in the Data Centre.

When I run iperf3 between the site and the host's WAN interface (i.e. bypassing the OPNsense firewall) I get 78Mbps, if I use the hosts LAN IP and go through OPNsense, I go back down to around 8Mbps.