Check your MTU values... ICMP Echo is only sending a 32 byte packet (+ IPSec 
overhead), so it will naturally be successful.  Vista, I'm sure, is sending 
much bigger packets.  To try and find your maximum MTU to set the connection 
to, you can use a Ping:

ping 192.168.1.1 -l 1500 (if it fails, decrement until it is successful)
ping 192.168.1.1 -l 1460 (decrement and continue if it fails...)
ping 192.168.1.1 -l 1400 (once successful, adjust your VPN to use the new MTU 
value)

HTH,

Aaron T. Rohyans
Senior Network Engineer
CCIE #21945, CCSP, CCNA, CQS-Firewall, CQS-IPS, CQS-VPN, ISSP, CISP, JNCIA-ER
DPSciences Corporation
7400 N. Shadeland Ave., Suite 245
Indianapolis, IN 46250
Office:�� (317) 348-0099
Fa������ (317) 849-7134
[email protected]
http://www.dpsciences.com/


-----Original Message-----
From: Lee Anderson [mailto:[email protected]] 
Sent: Tuesday, June 09, 2009 9:47 AM
To: NT System Admin Issues
Subject: VPN Tunnel not stable in Vista

Good Morning All,

I am having trouble with a VPN connection in Vista.  I am able to negotiate and 
build out the connection, we can ping across, but as soon as we send any 
traffic across it is dies.  XP machines work fine using same VPN endpoint.  I 
am running Vista Ultimate SP 1 and OpenVPN GUI V1.0.3.  I have turned off Vista 
basic controls such as firewall & IPV6.  Downloand 4MB upload 400kb.  The 
connection does not seem to be stable. Please let me know if you have an 
suggestions or direction.   

TIA
Lee
~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/>  ~

~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/>  ~

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