DI-624 VPN support

I'm trying to use Microsoft (XP) L2TP IPsec VPN on my computer behind the
DI-624, but have been unable to have it connect to the server (without the
DI-624 everything works), what do I need to do to get the VPN working (it is
enable in the set-up, and the DI-624 is working for other traffic (web
etc)).

I have revision C1 Firmware version 2.25 (10 Aug 2003).

"Geoff" <(E-Mail Removed)> wrote:

>I'm trying to use Microsoft (XP) L2TP IPsec VPN on my computer behind the
>DI-624, but have been unable to have it connect to the server (without the
>DI-624 everything works), what do I need to do to get the VPN working (it is
>enable in the set-up, and the DI-624 is working for other traffic (web
>etc)).
>
>I have revision C1 Firmware version 2.25 (10 Aug 2003).
>

What worked for me was to adjust the maximum sent packet size of my PC

For this, you have to add/change the MTU value in the registry,
for the appropriate network interface:

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Param eters\Interfaces\{<interface>}

"MTU"=dword:0000059e (hex for 1438)

The "1438" number is the maximum value of MTU for which it still
worked in my case. It can also be found as the max. value for which an
unfragmenting ping from the PC to the VPN server (company's firewall)
still works (have to add 28 to the value in Ping; Ping worked for up
to 1410). Use

PING -L 1410 -F 192.168.1.1

192.168.1.1 is the _private_ address of the firewall.

Or you may try the utility "DrTCP" http://www.dslreports.com/drtcp
which is said to adjust the MTU value automatically (I didn't try)

Alex