SG Broadband Community

I apologize in advance for the general question(s). I recently began using a VPN connection to access some work documents via file shares on our VPN. A majority of the files being accessed range from 5KB - 1MB. Generally small files, however connecting to the VPN and browsing is painfully slow. Opening and saving files is just as bad.

Questions:

• Can/should I tweak TCP settings on the server?
• Can/should I tweak settings on the client(s)?

Current Server Settings (Win Server 2008 R2):

• TCP Window Auto-Tuning: normal
• Windows Scaling Heuristics: disabled
• Congestion Control Provider: ctcp
• RSS: enabled
• TCPA: enabled
• DCA: disabled
• TTL:
• ECN Capability: disabled
• Checksum Offloading: default: n/a
• TCP Chimney Offload: automatic
• TCP1323 Options:
  • Window Scaling: unchecked
  • Timestamps: unchecked

Current client Settings (Win 10):

• TCP Window Auto Tuning: normal
• Windows Scaling Heuristics: disabled
• Congestion Control Provider: ctcp
• RSS:
• RSC:
• DCA:
• TTL:
• ECN Capability: disabled
• Checksum Offloading:
• TCP Chimney Offload:
• LSO:
• TCP 1323 Timestamps: disabled

Any help and suggestions would be greatly appreciated.

"Window Scaling: unchecked" This should be turned on.

I'd try turning off any TCP offloading and checksum offloading features of the NIC.
Try turning off jumbo frames (either on server or client).
If that doesn't work, try turning off RSS and Chimney offload (some older NICs may cope better with them off).

Ultimately, it depends on the available bandwidth on your server and the VPN protocol you use.

Thanks for the reply! If the following helps at all, are there any other tweaks that could/should be made? RSS and Chimney Offload settings on client, server or both?

As far as the VPN setup, it is PPTP. Speeds are as follows...

Server
Download: 91 Mbps
Upload: 40 Mbps

Client (Cable Company Advertised... I'd estimate 75% of this)
Download: 200 Mbps
Upload: 10 Mbps

I have not had a chance to check the connection yet, but I've updated the server settings as follows (changes in bold):

Current Server Settings (Win Server 2008 R2):
TCP Window Auto-Tuning: normal
Windows Scaling Heuristics: disabled
Congestion Control Provider: ctcp
RSS: enabled
TCPA: enabled
DCA: disabled
TTL:
ECN Capability: disabled
Checksum Offloading: disabled: 1
TCP Chimney Offload: automatic
TCP1323 Options:
Window Scaling: checked
Timestamps: unchecked

Thanks again for the reply. Appreciate the help!

RSS and Chimney Offload settings on client, server or both?

I'd start with the client, but you may have to do it on the server as well, if nothing else works. It could be one or more of the above suggestions, depending on the NICs and their drivers.

Hey Phillip -

I appreciate the help and replies. Just tried adjusting these settings, but the connection is still very sluggish.

As a test, I just transferred a folder from my server to my client computer over the VPN connection. The folder had 828 files and was a total of 15.3MB. Transfer speeds ranged from 1.5KB/s to almost 200KB/s, but the average transfer speed was probably around 18KB/s.

Uploading a large file from the client to the server, I'm seeing a steady spead of about 355KB/s with no fluctuation up or down. Which seems odd considering I have been doing other things while the file was transferring.

Again, I appreciate the help. Thank you.

Those speeds are terrible.. VPN is also dependent on CPU resources and type of connection (PPTP/L2TP/OpenVPN) and protocol (TCP/UDP). PPTP is the least secure and fastest to encrypt usually. Routers/Firewalls can affect it as well.

Have you tested those claimed speeds, can you get anywhere close to them without VPN from the server and client at all ?

Hahaha, yes... those speeds are terrible.

When I copy a file via FTP or even copy/paste via remote desktop the speeds are much better. Uploading from client to server is around 3MB/sec and downloading from server to client was around 15MB/sec.

Are there any diagnostic tools/tests that I can use to try to pinpoint a bottleneck? I've been googling all sorts of things, but have continued to come up empty.

Thanks again.

Well, just reset my router at the house to default settings. Pulling a bit more speed out of transfers, but there is still a large lag time when initiating a transfer as well as when browsing folders.