Slow client VPN speed

Here to help

Slow client VPN speed

Windows 10 client connecting to an MX64, authenticating using AD.

I am able to connect without any problem, however it is painfully slow.

Copy a file from a shared drive on the office network  runs between 170-350 kbps

We have a 10 mbps connection at the MX64 and a 150 mbps at my house.

Lots of bandwidth available at the MX64 uplink.

I have deleted and recreated the connection a few times, I am baffled.

I use some remote desktop connections to various servers on the corporate network that I have been using forwarded ports at the MX to connect via RDP, but I would like to shut those down and only use RDP over VPN.

The RDP connection is almost unusable over the VPN currently.


Kind of a big deal

This can be caused by an MTU squeeze.  Try an MTU of 1400 on your machine (reboot after changing it).  You can use these instructions for Windows 7/8:


You may have an issue with asymmetric timing.  You can try enabling timestamping with this command:

netsh int tcp set global timestamps=enabled


You could possibly be running an MX firmware with an issue.  I would upgrade to 14.39 if you are not running it already.

Thanks, tried the MTU change - no difference.

Ran out of time to try the  timing, will try this evening.

My MX is showing "Up to date. Current version: MX 13.36"
Kind of a big deal

@Microfiche 14.39 is a stable release candidate. It would be ok to upgrade.

Upgraded to 14.39 and recreated the VPN on my desktop.

No change at all.

Also enabled timestamping.

Switched my MTU back to 1500 as 1400 made no difference.

It almost looks like the speed is being capped because it is so stable at 177 kbps. Weird.


vpn copy speed.PNG


Looks like it is machine specific - connecting from my laptop works fine.

Both are Windows 10.

Kind of a big deal

When you mean works fine do you mean speed is correct on your laptop?

Kind of a big deal

In addition to the "what does works fine mean" question, how many machines are affected by this issue? Where is your laptop connecting from? 


Is your laptop on the same remote network as the device(s) having problems?

The laptop and the desktop are both connecting from my home network.

Those are the only 2 computers I have tested from.

The speed over the laptop VPN is similar to a non-VPN connection - hence fine.

The speed over the desktop connection seems to be about 170 kbps.

Kind of a big deal

Which is just around 1.42Mbps. Another good test would be to check speed on another wireless connection or (hotspot) see what your results are too.

@kYutobi wrote:

Which is just around 1.42Mbps. Another good test would be to check speed on another wireless connection or (hotspot) see what your results are too.

177 kbps = 1.42 mbps?


I will be in another province tomorrow, will try from there.

Comes here often

Can you check the speed of the NIC on the Desktop, if it is set Auto or has a different setup?

Set to auto negotiate. Connected at 1Gbps

Hi there Microfiche,


I know this is quite an old post, but did you ever find out the solution? I have a very similar problem. I have a remote user who is already on his second laptop in a month and I don't want to have to swap out another one just yet. Internet connection is great but it tanks on VPN. 80 Mbps all day when on regular internet, then it falls way down to 1 or 2 Mbps on our corporate VPN. No other users experience this. Thank you for you time!



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