Ac86u Merlin Openvpn server slow, but Client fast? ?

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New Around Here
Hi guys,

I've got what seems to be an odd issue.

I'm running both Openvpn Client and Openvpn Server on the single router. An Ac86 running the latest stable Merlin firmware.

To get this done, I followed a guide on this forum, where I setup a selective routing rule and installed a simple routing script under firewall-start.

This is all working, but I'm experiencing some performance issues in an interesting way.

With Openvpn Client only, I get 89mbit down, which is almost my entire 100mbit connection.

With OpenVPN Server and OpenVPN Client , I get 30mbit down.

With OpenVPN Server only, I get 10mbit down!!! I thought it was quite odd as to even without the extra hop to the Client, that the Server can be such a bottleneck. In fact, it even performs worse! Something must be going wrong there.

Does anyone know what could be causing this? I've tried a number of config settings, but I'm using defaults for server and client now.

I primarily test from my Samsung Note 20 Ultra Android device and Surface Laptop 3 with OpenVPN Connect client.


Very Senior Member
Not sure how you are testing this, but a limiting factor for the Server is usually your upload bandwidth. That is, if you are connecting from outside your house, through the server to the internet, the client device will download from the internet over a path that is from the internet to the server (normal speed), from the server to the internet (limited by upload speed and encryption), from the internet to the device (limited by download speed (cell or wireless, etc) and encryption).

Also, I find the Arne client better.


New Around Here
Thanks for the reply Elorimer!

I'm on 100/40. So would the theoretical Max download speed I can get via this method be 40mbit?

Any idea why Server alone gets 10mbit, but when tunnelled through the VPNs Client at the same time it gets 30mbit?

Not that I need to use Server alone, but it just seems like an interesting issue. I would have thought removing the hop makes it faster, not slower.

I'm using the Speedtest app and website to test.

I'll try the Arne client, thanks.


Very Senior Member
I'm on 100/40. So would the theoretical Max download speed I can get via this method be 40mbit?
Still a little confused on what you are testing. Let's say you are at the local Starbucks, on their wifi, and you are connecting to your OpenVPN server at home, because you don't want others in the Starbucks to snoop. You are surfing the interwebs through that OpenVPN server. You go to the speedtest website to test. Your speed will be limited by the slowest of (i) your wifi connection at the Starbucks, (ii) your upload speed from the OpenVPN server (in your case 40mbit), (iii) your download speed to the OpenVPN server from the internet (in your case 100mbit), and (iv) the processing power of your router (I don't see the 86U being the bottleneck here) and client device. Is this what you say is 10mbit?

Now complicate it further and say that your OpenVPN server is reaching the internet over the OpenVPN client to some VPN provider. Now the speed will be additionally limited by the upload speed from the VPN provider and the additional load of the second encryption. Is this what you say is 30mbit? I can't see how it could be faster.

To be honest, I've never set up the OpenVPN server to go out over the OpenVPN client to some VPN provider, because I've always connected to the VPN provider directly. I'm usually using that for geolocating video, for which I don't need the fun addon scripts like diversion and pixelserv.

In all of these disable compression.


New Around Here
Thanks Elorimer!

I just double checked, and compression is off.

What you've described is correct, which is what makes it extremely odd. I generally connect to my home network via OpenVPN on 4G or via my work Wifi. When the OpenVPN Client on my Router is also on, then I get 30mbit. But when the OpenVPN Client on the router (connected to NordVPN) was inactive, the speed dropped to 10mbit.

I don't need to use it that way, so it's not really an issue for me. I just thought it may explain why my general speed is quite low, if the OpenVPN server was somehow bottlenecking the connection. Maybe it was the script I setup to tunnel the traffic from the router's Server to Client.

But ta the end of the day, if my ISP's upload speed of 40mbit is going to be the bottleneck for download speeds when using the OpenVPN Server, then I think I should just be happy with 30mbit. Especially considering it then tunnels through the OpenVPN Client too.


Very Senior Member
30 mbps over a 40 mbps pipeline sounds pretty reasonable. Remember that there is overhead associated with the OVPN transport packet. And the added latency of VPN can affect the speed of some protocols.

Why don't you connect directly to NordVPN when not at home?
Last edited:

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