Ok, I searched for an answer before asking. I found related issues, but nothing that is helping me.
I have a Cisco PIX 501. It's working.
I have two remote clients that can connect via VPN. They work great.
I tried to set up two new clients, but they refuse to connect, giving the "Unable to contact the remote gateway" error. (That's 403, as I recall.) These clients are in a remote location. In the office, I set up those same two clients outside the firewall (behind another firewall) and I still cannot connect via VPN.
Both "new" systems have functional Internet access. So, I did a telnet xx.xx.xx.xx 25 from both clients to verify that I could *reach* the gateway. I was able to connect to the mail server.
I briefly looked at the Cisco log, but the system I had to use was very slow, and I couldn't wait for the log to update, but the only real errors I saw were something about an "spi" problem on an incoming connection. I didn't have the time to verify that it was the address I was coming from for my testing.
So I am stuck. I'm planning on calling Cisco for help, because I have to get these working, but if someone here has a suggestion, I am all ears!!
-- Rob --