I wfh a couple days a week, our office has an Sonicwall firewall device, which we use to connect and transfer files, etc. We’ve used it since 2018/2020, works as advertised.
The issue - my home network, my fileserver and pc are both hobbled at 25-50% capacity by SIMPLY having the Global VPN client installed (4.10.8.1108). Removing the software, and rebooting nets me full gigabit wired connection. That said, once reinstalled and after connecting to the office, it affects my network speed. Rebooting and not launching the software still effects my speed. My fileserver is using the latest version of Win10, and my PC latest version of Win11.
I should note, this is SMB file transfer speeds, as well as testing with iperf. I’m not an IT level expert, and don’t have direct access to the hardware settings in office, that is run by the bosses IT friend.
Sounds like a DPI-related issue.
If possible, try switching to SPI (if you even have that capability to do so) & see if that helps.
I updated to the latest version today, and had the same issue. Now after posting this, its back to full speed. So confusing.
I’ve had the segment coalescing issue before, where my HTTP speeds were down to nil. If memory serves me, I did install the windows hotfix, which fixed the issue back then. Since, I’ve not had to install that fix, my web speeds where well above 1mbs.\
I think this issue is separate, granted I did try the hot fix again. It’s seemingly “random” now. I could go into detail, but I feel confident its separate.
Is that a hardware side change? All I have is this little piece of software.
Forget the “fix” and just do it yourself. Either disable RSC per adapter:
Disable-NetAdapterRsc -Name “INSERT ADAPTER NAME”
Or just disable it globally:
netsh int tcp set global rsc=disabled
The problem is your consumer based adapter drivers either don’t support RSC or has bad support for it. Either way it needs to be turned off.
I’ve ran into this with the Global VPN client and with VM speeds on consumer based 10Gb cards because Microsoft turned on RSC for anything 10Gb.
That’s typically gonna be on the hardware side.
All of your traffic isn’t going over the VPN is it? (I.e., are speeds to the office network(s) slower than to google.com, or are they both slow)
The issue is the slowdown that occurs: 1. After the vpn software is installed on the home client pc and home file server 2. Home client pc tries to copy files (SMB) from file server. 3. File transfer speeds are reduced by 25-50%. 4. If both the local home pc and local home “file server” uninstalls the vpn software, speeds resume at 115ishMB/s.
This all happens independently from the vpn software running. The very act of having it installed will randomly affect speeds.
I see - the speeds between 2 devices on the same local net are effected.
I assume you’re using NetExtender?
Also, is the issue present if you install the app but don’t connect it (for the first time)?
Not sure what NetExtender is, so no.
I did a test installing the app, but not connecting, in that case my speeds were fine. Once I established a connection after the install, I closed the connection, and copied a file locally, my speeds were effected downward again.
Then I posted here, did another test, and speeds were fine (I did nothing?). So, it’s kind of random, maybe something else going on now.
In that case, maybe something with the VPN tool you’re using? I’m not sure. Maybe check the tool to see if there’s some kind of speed/bandwidth management that it does, or possibly something to do with it’s priority.
I’m out of ideas - heading off 
Good luck 
