Solved OpenVPN Client: help debugging slow speed issue

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amoney

Occasional Visitor
Recently i noticed that my vpn client was only getting about 10-15Mbps speed which is lower than what i had seen earlier 40-50Mbps. I confirmed with the VPN (Mullvad) provider that there were no issues on their end and then i did the following test.

1. Connect my mobile device directly to internet: 300+ Mbps
2. Connect my mobile device directly to mullvad openvpn: 300+ Mbps
3. Connect my mobile device to mullvad vpn via my router: 10-15Mbps

Main Router
RT-AC88U: 386.3_2
Mesh Node:
RT-AC68U: 3.0.0.4.386_43129-g60defb2

I also noticed that when i was doing the speed tests CPU on both core's would spike to 100%. What i can recall from earlier is that it would only spike to 100% on one of the cores.

Any pointers on what I should look at to help improve the speed of my vpn client?

Edit: Solved after reboot :).
 
Last edited:

L&LD

Part of the Furniture
Are you sure you're testing by connecting to the same exact server?

Do you have HW acceleration disabled in your router?

What other features and options are enabled in the router? Many of these will disable HW acceleration and decrease your VPN speeds.
 

amoney

Occasional Visitor
Yes connecting to the same server. They have multiple servers in the location i am testing with and all of them get about 10-15Mbps via my router.

Under Tools -> Sys Info it says hardware accelation is enabled.

As for other features and options i have YazFi, Scribe and uiScribe running. Some port forwarding, vpn server running and thats about it. I have PiHole running so i update dns settings but i imagine if that was an issue i would have seen issues with my other test runs.

Is the CPU spike to 100% on both cpu's expected? Am i mis rembembering that it would spike to 100% only on 1 of the CPU's?

Edit:
Forgot to add. I have traffic history enabled as well, but it has been enabled for a long time and was enabled when i saw 40-50Mbps. Per IP monitoring is disabled (I think thats one of the things that disables hardware accel)
 
Last edited:

eibgrad

Very Senior Member
Worst case, you could always make a backup, then reset to factory defaults, manually reconfigure *only* the OpenVPN client, and see what you get in terms of performance. If things return to normal, you know the problem lies w/ some combination of additions you subsequently made. Let's face it. There are so many features, so many third-party scripts, etc., the opportunities for conflicts abound on these routers. And it's anybody's guess where those conflicts may lie.
 

amoney

Occasional Visitor
Worst case, you could always make a backup, then reset to factory defaults, manually reconfigure *only* the OpenVPN client, and see what you get in terms of performance. If things return to normal, you know the problem lies w/ some combination of additions you subsequently made. Let's face it. There are so many features, so many third-party scripts, etc., the opportunities for conflicts abound on these routers. And it's anybody's guess where those conflicts may lie.
Yup will leave this as the last resort, not looking forward to it lol.

In terms of features i have not changed anything in my router for a long time, other than just doing the various firmware updates. But like you said it will be difficult to find the issue without doing a clean setup.
 

L&LD

Part of the Furniture
Have you tried a simple reboot of the router (via the GUI) and then waited 10 or 15 minutes before testing again?

Have you tried using a different VPN Client position?

Do you have any VPN customizations on the router?

Have you tried simply re-flashing the same firmware that is currently on the router?

Are you positive that all your scripts, Entware, and other bits are fully up-to-date?
 

amoney

Occasional Visitor
Have you tried a simple reboot of the router (via the GUI) and then waited 10 or 15 minutes before testing again?

Have you tried using a different VPN Client position?
Ah yes need to try a reboot. Dont know how i forgot to give this a try :). Will report back on the reboot and a different client positions.

Do you have any VPN customizations on the router?
Regarding vpn customization, is this the Custom Configuration section? If so this is what i have in it
Code:
resolv-retry infinite
remote-cert-tls server
ping 10
ping-restart 60
sndbuf 524288
rcvbuf 524288
tls-cipher TLS-DHE-RSA-WITH-AES-256-GCM-SHA384:TLS-DHE-RSA-WITH-AES-256-CBC-SHA
tun-ipv6
fast-io
mute-replay-warnings
pull-filter ignore ifconfig-ipv6
pull-filter ignore route-ipv6
comp-lzo no
remote xxx.mullvad.net 1302
remote yyy.mullvad.net 1302
remote zzz.mullvad.net 1302
remote-random

Have you tried simply re-flashing the same firmware that is currently on the router?

I was not even aware that I could do this. Will give this a try as well.

Are you positive that all your scripts, Entware, and other bits are fully up-to-date?

Yup, i periodically check everything is upto date. Checked again and everything is upto date.
 

L&LD

Part of the Furniture
Always try the simplest things first. :)

 

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