Encouraged by this thread, I finally dared to install vpnc 0.5.8-0m5 from extra-devels, and found that I could use it exactly as I was used to on my Debian laptop. I could use it while on WLAN and even while on the cellular network, though I noticed that at one point /etc/resolv.conf became empty. So I restored it manually, but when it happened again, I found that it didn't seem to make any difference whether I restored it or not (neither when using WLAN or the phone network). I'm now leaving /etc/resolv.conf empty, simply because I wanted to see what's the difference. Can anyone tell me?

So, at least for me, the connectivity of the N900 doesn't leave any wishes open after having successfully installed ssh client and server, and now vpnc, which I need to connect to the Cisco concentrator run by the university I'm working at.

Kudos to maemo.org !!

PS: Since this thread started with issues about the GUI of vpnc, I should perhaps also say that I didn't try that. It's anyway more convenient for me to have vpnc started by a script, and having the necessary configuration in /etc/vpnc. Doing so, I didn't have any problem regarding non-numeric characters in username and password.