I have setup VPN server in ISA 2004 with SP1 and the OS is win2000 Advanced server with SP4. All my clients are able connect to the VPN using wired DSL connections from their sites but not with wireless connection. The error log in the ISA is this
Description: The VPN connection attempt by user ISA\ sales could not be established.
The failure is due to error: 0xc0040021 in the system event log it says the user sales couldn't authenticate because of bad user name and password.
Nice to hear from you. This is my problem. I have setup VPN in ISA 2004 and it is working fine. The VPN is mainly used by our marketing team. One of them has a wirelss DSL Connection at his place. His ISP has set up a wirelss 3 com ADSL router at his place and he is connected to this from his lap top (this lap top is configured and supplied by us).He is not able connect to the VPN through this connection. It seems that the L2TP and PPTP are disabled in his router because in the log it says that this particular user connected but the authentication failed due to bad user name and password. This same user get connected to the VPN from the normal dial up connection.
The real test would be to see if the user can connect when he uses a wired connection to the wireless NAT device. If there is still a problem, it could be a NAT device configuration issue, or maybe an MTU problem, or something else :)