L2TP/IPSec RAS VPN speed boost?

Home office
-Win Server 2003 SP1 (std edition)
-2.66 Ghz / 500MB RAM
-ISA Server 2004 Std Edition with SP1

Remote user:
- Win XP SP2
- 2.4 Ghz / 500MB RAM
- Cox cable modem
- Cable modem speedtest is 1900 kbps down, 500 kbps up (via speakeasy.net)
with no VPN active
- Certificate installed via Tom Shinder's articles from our Exchange 2003
server (for VPN)

Our ISA machine is never under a load and it performs well. Months ago, we
setup a L2TP/IPSec VPN with a certificate from our Enterprise CA on the
Exchange 2003 server. We also run forms based OWA all using isaserver.org's
articles.

>From the remote machine, I happened to notice that when the VPN is active,
downloads (and uploads) move at about 40% line speed (from/to the home
office). When I download from the web, its closer to line speed. So the
VPN processing is slowing it down considerably.

We will be retasking the ISA server machine (for other reasons) and I get to
spec out new hardware for ISA. All is well but I would like VPN to work
much faster. I would think that the VPN encryption/decryption on each end
is slowing it down. Perfmon doesn't really reflect this and I am just not
so sure. We have a 100 user LAN, a handful of VPN users (<5), and run OWA -
all on a T1.

Can anything be done to boost VPN speeds? Should I buy more ISA machine
(CPU/RAM/a special VPN card)?

Thanks,
dmeade


.

Relevant Pages

  • RE: VPN Connection Problems
    ... Note that we are able to successfully VPN into the office. ... to browse the network, RDP to the server or even ping the server. ... > This newsgroup only focuses on SBS technical issues. ...
    (microsoft.public.windows.server.sbs)
  • RE: VPN issue on SBS2003
    ... I understand that you encountered VPN connection issue when you use VPN to ... Internet clients or VPN to external VPN Server from SBS Client computers? ... Configure E-mail and Internet Connection Wizard ... Total GRE packets sent = 1 ...
    (microsoft.public.windows.server.sbs)
  • Re: ISA2004 kills VPN outbound
    ... Extract all files to a folder on ISA server. ... Expand the server node and highlight 'Monitoring'. ... After the VPN connection was established, ... |> Since the branch office workstations can connect to the VPN server, ...
    (microsoft.public.windows.server.sbs)
  • Re: Windows 2003 VPN Default Gateway Issues
    ... on the same subnet as the server leads me to believe it was a routing ... Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net ... How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com ... the default gateway on the client is not the problem. ...
    (microsoft.public.windows.server.networking)
  • Re: Secure VPN access
    ... with it's security option for the client. ... After getting the VPN connection I check the Ip settings and found the ... point to the head ISP's DNS server. ... > Computer certificates for L2TP/IPSec VPN connections ...
    (microsoft.public.windows.server.sbs)
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