VPN Issue - System i (As400) sessions drop, only on VPN

Unanswered Question
Feb 9th, 2010

Hi folks, looking for your help. we are using the Cisco VPN client 5.005. When users connect from home to our System i (as400), sessions drop, even when users are actively using their system i sessions. In doing some research, and contacting IBM, it seems to be a network/VPN issue. The system i is not ending the usrs session, after they lose their connection, the session is still active on the System i. IBM stated everytime this issue has arised it has never been on the system i side.

Users who are local do not have this issue, it seems just to be when conencting remotely. The network team here swears there is nothing they can check, as the VPN is fully open, and they have checked the firewall settings. Does anyone know what may be the issue or have had this usse and got it rectified?

I have this problem too.
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jimsiff Sun, 02/21/2010 - 01:40

Just a stab in the dark... I've seen strange session disconnect problems when VPN concentrators are set to rekey the Phase 2 encryption key after a small data lifetime.  If the VPN concentrators are set to rekey every 5-10 MB of data, and the user is syncing a mailbox, downloading large files, backing up the PC, etc... this can trigger a rapid rekeying scenario where the client's As400 TCP session is hammered enough that it is disconnected, even though the VPN remains "up".

If your network admins require a short data lifetime on their IPSEC Phase 2 definition, ask that they create a new Phase 2 proposal for testing with a very large data lifetime.  Rekey should still occur based on fixed time intervals... usually 1 hour by default.

Hope this helps...



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