OpenVPN client and server degrading download speeds

[agent5150]

Just updated my RT-AC68U to 384.5 merlin firmware and noticed that my 100Mbps down speed is now merely 35Mbps. Direct connection to cable modem shows 100mbs down speeds no issue. started trouble shooting the router, turning off VPN server and client and rebooting brought up the down speeds to 100Mbps at the router. Turn VPN client back on, and speeds at the router nose dived to 35Mbps again.

Is this normal? I have been using both OpenVPN client and server on previous firmware versions and never had such speed drops. anyone else observing this behavior? Tried rolling back to 384,4-2 and that didn't; work either, router rebooted and still on 384.5. Any suggestions?

 

[ColinTaylor]

35Mbps through the VPN client is about right for the RT-AC68U. If you were getting your full line speed (100Mbps) before then you weren't going through the VPN, the router simply isn't powerful enough to deliver anything like that speed.

 

[agent5150]

35Mbps through the VPN client is about right for the RT-AC68U. If you were getting your full line speed (100Mbps) before then you weren't going through the VPN, the router simply isn't powerful enough to deliver anything like that speed.

I meant to say I am getting 35Mbps on non VPN rounted internet access. Clients going through VPN client are even slower.. barely 12Mbps.

 

[Zastoff]

How does your Rules for routing client traffic through the tunnel look like?
If you use 192.168.1.0/24 for routing all client through vpn you need to add 192.168.1.1(Router) to wan or you can get wierd results

 

[Xentrk]

Just updated my RT-AC68U to 384.5 merlin firmware and noticed that my 100Mbps down speed is now merely 35Mbps. Direct connection to cable modem shows 100mbs down speeds no issue. started trouble shooting the router, turning off VPN server and client and rebooting brought up the down speeds to 100Mbps at the router. Turn VPN client back on, and speeds at the router nose dived to 35Mbps again.

Is this normal? I have been using both OpenVPN client and server on previous firmware versions and never had such speed drops. anyone else observing this behavior? Tried rolling back to 384,4-2 and that didn't; work either, router rebooted and still on 384.5. Any suggestions?

I concur with @Zastoff.

I have experienced degraded OpenVPN client performance after making firmware upgrades. This has not happened on all firmware upgrades. But enough to know that I am always prepared to perform a factory reset after an upgrade if need be. A factory reset always restored speeds to their normal (albeit still slower than native WAN) speeds.

You can try adding the fast-io line to the Custom Configuration section for a modest 5% gain. Use GCM cipher with SHA1 rather than CBC cipher for improvement.

Here are some other references:

https://x3mtek.com/openvpn-performance/
https://x3mtek.com/torguard-openvpn-2-4-client-setup-for-asuswrt-merlin-firmware/

 

[agent5150]

How does your Rules for routing client traffic through the tunnel look like?
If you use 192.168.1.0/24 for routing all client through vpn you need to add 192.168.1.1(Router) to wan or you can get wierd results

I am not routing all clients. only specific clients. Never seen such massive bandwidth loss on non vpn routed clients with older firmware.

 

[Zastoff]

I am not routing all clients. only specific clients. Never seen such massive bandwidth loss on non vpn routed clients with older firmware.

Add 192.168.1.0/24 to wan in selective routing and keep the clients you want in there for vpn just to make sure..
Or try Factory reset as @Xentrk said