A “big” problem happened to me over the last month: unexpectedly (I suspect it was some microsoft update) the cisco vpn client stopped working, or better, the client was connected but I could not reach anything on the customer's network, What's even more strange routes created were correct but if I tried to do a traceroute to a remote network ip packets trying to leave from the default gateway instead of the vpn gateway (!!!).
After days wasting time looking for some solution, I noticed that other vpn clients gave me problems such as sonicwall netextender would not even connect (I forgot to write down the exact error but it gave error in the final authentication step if I'm not mistaken). Even more strange other vpn client worked without problems instead (i.e.. the Palo Alto firewall client). Doing more testing (and meanwhile the days passed…) I noticed that even the simple microsoft pptp vpn did not work and gave back a “error code 720”. This last error pointed me towards the final solution because at this point it was pretty clear that it was an operating system issue, and I imagined that some vpn client were bound to something that was no longer working properly, while others were not.
After some research the problem appeared to be related to wan miniport that no longer worked properly.
The most comfortable final solution I found it's here:
On this page you will find two simple executable that allow you to remove and recreate wan miniports restoring them to their initial configuration with a couple of restarts. These are the 4 simple steps to solve (the tool can be found on the site to which I refer):
1. run Wan miniport repair tool (or version 2)
2. restart computer
3. run Wan miniport installer
4. restart computer and enjoy fully working Dial-up and VPN access again.
I hope will be helpful to someone considering the time that I lost to solve it!!!