Powerline and corporate VPNs - are they incompatible? A headscratcher...

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Having just moved house, I noticed the wifi in my study was patchy. I therefore invested in a TP Link Powerline (TL-WPA4220) to run from my router to my study.


It works perfectly on all my personal devices (Windows, Apple, Android etc) with them all getting the full wifi speeds promised by my ISP (Vodafone), both over wifi and ethernet. 


The main reason I installed this, however, was for a fast reliable connection to my work computer. But whether via wifi or ethernet I'm getting much slower speeds on my work laptop than my personal devices connected to the same powerline - even slower than before I installed it when I was working at the far edge of my router's range. I'll be getting 70mbps download and 25mbps upload speeds on my personal devices and 2mbps download and 5mbps upload on my work computer.


I called my work IT, they suggested my ISP was throttling my use (when testing the connection on my work laptop we found that when I connected to my ISPs network / server the speed was as expected, but any other server was very slugglish, which led them to think this).


I contacted by ISP who insist they're not throttling my use and it must be something to do with my employer's IT policy. They did give me a static IP address suggesting this might help (but it hasn't).


Any ideas why this might be happening?My main suspicoion is that it's something to do with the VPN on my work laptop (zscaler), although when I tried installing a VPN on my own persional laptop it had no effect on speeds. How could my laptop / VPN even recognise that my internet is coming from a different source? Are there any known issues with powerlines accessing secure VPN networks?


I'm being bounced around to different people none of whom have a clue, so any advice would be gratefully received!

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Well when you connect your work laptop direct to the router, and connect to the vpn do you see this same speed reduction?


If so then it rules out the powerline connection.


15 hours ago, EVJOHN said:

Are there any known issues with powerlines accessing secure VPN networks?


Not that am I aware of - and it makes really no sense.  The powerline adapter has no idea that your traffic is vpn or not vpn traffic.  They do not care what traffic is moved - they just transfer the packets.


How exactly are you testing this speed?  Like a speed test site?  You understand that running through a vpn forces all traffic to your work network, So speedtest would flow through your work network which could cause slow downs for such testing.  A vpn is normally going to be a hit on performance anyway - because you have added overhead to the traffic because your inside a tunnel.   How much that is has many factors to take into account.


Unless your vpn software allows for split tunnel, where only work related traffic goes through the vpn, then it is to be expected to see a drop in speed when doing say a speedtest.net sort of test.


So again - I would just take the powerline out of the loop for testing.. Connect the work laptop to the router directly, using the same cable.. What do you get now for speed testing?

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