VPN Connection Dropping ALL THE TIME!!!

[wraights]

I have a PIX 515 and many many VPN clients spread across. They connect using VPN 3.1 and above clients (depending on which OS they have). They all have cable modems and none have been having trouble...UNTIL THIS ONE.

She is consistently having trouble and I can't figure it out. She had her cable installed and she was working fine for about 2 months. Then her cable went out for about 2 days and ever since, she has had trouble. She will connect to us using the VPN client and after about an hour, she will have her VPN connection terminated. When she is connected to us, she telnets to a UNIX box we have. Sometimes just her telnet screen disappears and she can get another telnet screen but most of the time just the whole VPN connection is terminated.

So I called the cable company thinking that something was wrong with the cable. They tested the line and replaced her cable modem. Even when her VPN connection is terminated, she still can browse on the web and ping on the Internet. And she can reconnect with NO trouble, but once connected she seems to get disconnected all the time.

Is there something more I need to ask the cable company to check? Could it be something in the TCP/IP stack that they are blocking or something wacky that I can change on our side? Another thing...I switched out her PC with one that I have personally tested and it worked fine with me on my cable modem, but with her, it terminates all the time. I am at a complete loss at what it could be. ANY ANY thoughts are gladly welcomed.

[afakhan]

Hi,

Logs from the client and concentrator side should help here, it looks like a DPD issue, where client disconnects itself thinking that headend is no longer alive.

Are you using ipsec/tcp, or udp, do you see same thing with both?

Thx

Afaq

[wraights]

We are using ipsec/tcp.

Unfortunately, we are not using a concentrator. This is straight up on the PIX and I do not have any logs. What would cause it to think that the connection is no longer alive? That is what I was thinking, that for some reason it was thinking that the connection should be terminated. And why only this ONE person? Thanks for your help...

[roraver]

If this is the only user that is having the problem then you will have to look at the user specficics. What makes this user different then the rest? Different ISP, Apps, etc... Like stated above, the debugs in this would really be helpful. Does the disconnection happen at the same time every time or is it at random? Is the user doing anything that could be triggering this?

[wraights]

Yes it is the only user having problems. Unfortunately, there isn't much different about her. She is using the same apps and the same ISP. The disconnection seems to happen at random times. I don't think that the user is doing anything to trigger this as I have just been there when it randomly disconnects. I wish I had some debugs. I guess I could run some on the firewall...the thing is that it would become very large very quickly as we have many many people connecting through this firewall...Any suggestions on that?