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SonicWall VPN slows to a crawl

Highside
Grafter
Posts: 33
Thanks: 15
Registered: ‎30-09-2016

SonicWall VPN slows to a crawl

The office have a SonicWall VPN host and I have the client at home.
Most of the time everything works flawlessly and I use Remote Desktop to work on the Office PC.

Pinging the work PC from home PC gives a pretty reliable 30ms ping and file transfers happen at several MBytes/s.

This is all on Windows 10 with a PlusNet HubOne  on Unlimited Fibre with a static IP (81.x.x.x)

The problem is that Occasionally the VPN slows to a crawl and seems to start dropping packets.

Remote Desktop becomes unusably laggy and sometimes disconnects completely. Copying files slows to a crawl - sometimes a few hundred bytes per second. This can last for hours.
Pinging the work machine times out sporadically and also sometimes gives ping times of 1 or 2 seconds.

Funnily enough, throughout all this, the VPN just says it is connected - although it does say bandwidth is very low.

While these VPN problems are happening, accessing any other site from the Home PC works fine and is fast. Broadbandspeedchecker says I am getting the 25Mbps which is normal for me.

Rebooting either or both PCs does not help. Turning off all other machines on the Office LAN does not help.

Eventually, for no apparent reason, the VPN recovers and works fine again.

Office IT department swear blind it is nothing to do with them and that their internet connection is not getting swamped.

They did point the finger saying "several ISPs do throttle vpn traffic to save the overall bandwidth available".

So the questions for this forum are:
1) Does anyone know if Plusnet does this vpn throttling thing and if it might be the cause?
2) If not, then any suggestions what might be the cause?
3) Any suggestions for further troubleshooting?

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1 REPLY 1
MisterW
Superuser
Superuser
Posts: 14,773
Thanks: 5,539
Fixes: 395
Registered: ‎30-07-2007

Re: SonicWall VPN slows to a crawl

Plusnet do not throttle Vpn traffic , in fact they don't throttle  any traffic .

Given that your normal Internet traffic isnt affected it does tend to point to an office problem

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.