Anyone seeing VPN connections rate limited?

Hi, a contact connects to a VPN endpoint on my network using IPSec.

I'm on Zen and they are on PlusNet, but we are both on 40/10 packages.

Normally they can access a shared folder at 10Mbps as you would expect but this week the same connection is only running at 2Mbps.

We have both checked our internet speed separately and are running at 37/9 for normal connectivity.

For another test from a smartphone I switched from Wi-Fi to 4G and connected back to my own VPN from the Internet, and throughput was still normal, not limited to 2Mbps so that really only leaves the far end.

Anyone else seeing VPN usage limited by PlusNet
(including maybe some different prioritisation of traffic types applied in evenings)
given that more of us are home working and with different working patterns so need secure connections to work as normal?

Edited by prlzx (Wed 18-Nov-20 20:03:46)

Reviewing the document About traffic prioritisation

though it appears this should not apply to unlimited FTTC so I'll have to check if that is what they are on.

I just tested throughput on my OVPN server hosted on PN Business FTTC.

Line sync is approx. 15Mbit upload. I'm currently away from home on a BT residential FTTC connection (55/10) and am seeeing 13Mbit from the OVPN server to me, which is about what I'd expect given all the overheads.

Thanks, that is helpful in terms of data points,
but in this case the remote VPN client is the one on a PlusNet connection (not the local VPN server).

So I left my router live graphing open for a while and I could see their connection occasionally shift up to 9.xMbps for less than a minute but then shift back down to 2Mbps or less, in a very binary way (step changes and not variable speed).
It was like they were being toggled between 2 distinct states - curious.

I also asked them to check that they could still run a speedtest at normal speeds while their VPN throughput was reduced (and it's a split tunnel so only destinations inside my network run over the tunnel).

I also asked them to check Windows 10 wasn't running updates.
They've disconnected now but a 45 min transfer took over 5 hours and until after midnight.

Edited by prlzx (Thu 19-Nov-20 01:30:49)

It could possibly be Windows 10 (I'm presuming the remote client is a Windows device) - not the connection itself.

Windows 10 uses bandwidth quite conservatively when the client is copying small files. On our gigabit network at work, we frequently see small (upto 20mb) files only having very small transfer rates, whereas when transferring large files, it jumps quite alot.

You didn't mention the types/sizes of files that were being accessed, but the above is a suggestion

I added OpenVPN to a Plusnet customer this week, standard setup with UDP over port 1194. Could see end to end traffic via a PCAP but continually failed on initial TLS handshake. Reading through Plusnet forums there appears to be an issue with VPN if you have a 146.x.x.x IP. Their support fixes are power cycle the router to get another IP and they don't support VPN so are unable to perofrm any troubleshooting.

Thankfully customer was happy to hotspot from their mobile as a work around.

In this case it was one 3GB file accessed using an internal-only web server.

Yes on copying larger numbers of smaller files, I have seen Windows be less predictable, and with other OSes can also depend on the filesystem and storage

However in any event regardless of storage factors Windows as a client would normally be able to sustain the 1.2MB per second to max out the FTTC upload at my end, instead of the 250KB per second (~2Mbps) it was running most of yesterday evening.

And as per the previous post from a smartphone out on 4G connecting to the same VPN locally was about 5x faster.

Anyway I am not expecting to a fix or workaround only to know if anyone has experienced something similar now that PlusNet and other ISPs need to cope with more home working probably more consumption on streaming services too.

Reading between the lines of example support responses PlusNet class VPN as a business use case rather than a generic protocol for securing traffic between 2 homes.

Edited by prlzx (Thu 19-Nov-20 16:41:52)

In reply to a post by prlzx:

Reading between the lines of example support responses PlusNet class VPN as a business use case rather than a generic protocol for securing traffic between 2 homes.

And that is rather telling as the whole internet is held together with vpns