Slow VPN with single WAN, fast VPN with dual WAN

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Mr. Nightsea

Occasional Visitor
Hi all,

My setup:
  • Asus RT-AX88u
  • Latest version of Merlin running
  • VPN Provider is NordVPN
  • Dual WAN configured: Load Balancing 1:1
  • IPS Connection: Fibre 600/600

Why is it that when I’m connected to my VPN provider (VPN Client), setup in the router, and have single WAN setup, my computer goes through the tunnel, I only get about 10Mbps.
When I setup Dual WAN, keeping the rest is the same, I’m maxing out my connection.

ipleak shows in either situation the VPN server I’m connected to. In not one of these situations my ISP is shown/revealed.

I’ve tried connecting to multiple different VPN servers and all have the same result.
Any suggestions are welcome.

Thanks
 
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L&LD

Part of the Furniture
What router model? What firmware version? What VPN? Be specific.
 

Mr. Nightsea

Occasional Visitor
What is the Dual WAN load balancing doing with a single ISP connection?
Well, I've connected it to an Eth port of my ISP modem initially just to try the feature see how it works, I was already connected with my VPN and all.
Then Restored my setup to single WAN and noted the difference (drop) in speed. Changed to various other VPN Servers, no luck. Configured Dual WAN again and maxing out my connection.

I have no idea why this is happening, haven't found satisfying info online yet.
Are my requests from my devices going out through the WAN port and replies coming in through the Eth port?
Am I exposed to the internet now, or in other words I might as well just turn of my VPN tunnel? Even though IPLeak and DNS Leak Test doesn't show any leaks.
 

L&LD

Part of the Furniture
'Latest version of RMerlin' means very, little. For example, I'm running RT-AX86U_386.4_alpha1-g8f4afe6890 myself.

Changing settings back and forth does not give a stable network experience (in my experience). Your situation is a good example of this.



If you haven't done so already, I would follow the suggestions below to get your router to a good/known state.

Fully Reset / Best Practice Setup / More
 

Tech9

Very Senior Member
Am I exposed to the internet now

Restore your single WAN configuration, reset your VPN client. Expect about 180Mbps on OpenVPN with 386 code firmware. If you see significantly faster speeds, you perhaps have IPv6 leak. IPv6 is not supported in router’s OpenVPN client. If you have IPv6 enabled, disable it and try again. You lose nothing running IPv4 only.
 

Mr. Nightsea

Occasional Visitor
'Latest version of RMerlin' means very, little. For example, I'm running RT-AX86U_386.4_alpha1-g8f4afe6890 myself.

Changing settings back and forth does not give a stable network experience (in my experience). Your situation is a good example of this.



If you haven't done so already, I would follow the suggestions below to get your router to a good/known state.

Fully Reset / Best Practice Setup / More
Latest version for me is: 386.3_2

Already did a couple of resets for problems with DNS servers, but I'll try to do this again during the next week.
See what happens.

But why won't speeds go up above the 180Mbps (more or less) ?
 

Tech9

Very Senior Member
But why won't speeds go up above the 180Mbps (more or less) ?

This is what home router hardware can do. Your RT-AX88U is one of the best. For higher speeds on OpenVPN you’ll need x86 CPU based router/firewall. You may explore Wireguard options available.
 

Mr. Nightsea

Occasional Visitor
This is what home router hardware can do. Your RT-AX88U is one of the best. For higher speeds on OpenVPN you’ll need x86 CPU based router/firewall. You may explore Wireguard options available.
Bummer regarding the speeds...
But still I'm curious why my speeds are way up when using Dual WAN?

WireGuard is available for Asus Routers?
Will check this...
 

Tech9

Very Senior Member
I told you already. The only way to see abnormal high speeds on OpenVPN is IPv6 leak, if you have IPv6 enabled. The data goes around the VPN tunnel. It could be also speed measuring error. Fast.com regularly shows speeds above my actual ISP speeds, for example. Dual WAN on Asuswrt is not reliable, I don't know the inner workings. I believe it's a closed source code from Asuswrt.
 

Mr. Nightsea

Occasional Visitor
I told you already. The only way to see abnormal high speeds on OpenVPN is IPv6 leak, if you have IPv6 enabled. The data goes around the VPN tunnel. It could be also speed measuring error. Fast.com regularly shows speeds above my actual ISP speeds, for example. Dual WAN on Asuswrt is not reliable, I don't know the inner workings. I believe it's a closed source code from Asuswrt.
Yes you told me already....IPv6 is DISABLED.
 

Tech9

Very Senior Member
The CPU used in RT-AX88U could process about 250Mbps OpenVPN on 384 code base firmware, but maxes out at about 180Mbps on 386 code base firmware. RMerlin mentioned some changes/reasons somewhere on SNB. OpenVPN uses a single core and this is what ARMv8 core with AES support can do. The routers with no AES support can't process even 100Mbps. If you see something different, like much higher speed number, it's not possible. If you think your router's configuration is messed up, restore it back to factory defaults and set it up again manually. I don't know how OpenVPN Clients in Asuswrt-Merlin deal with Dual WAN load balance configuration. It's quite possible in one direction you use the VPN, in other WAN. @RMerlin may have more details about it. Dual WAN doesn't miraculously speed up your VPN.
 
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