Using the Shrew VPN Client with Windows 8 (not 8.1) and a remote firewall Netgear FVS318v3: Everything runs fine.
After upgrading to Windows 8.1, it seems to work first and the connection gets established – but a ping to your remote location fails.
In some forums people describe that it helped when they uninstalled, rebooted and re-installed Shrew, but that did not do it for me.
At this time there seems to be no solution for Shrew 2.2.2, we will have to wait for an update (or maybe try a Windows 8.1 installation from scratch…).
However, I figured out that an alternative software works under Win 8.1: TheGreenBow VPN Client
(looks like it’s the same software as Cisco VPN Client, but with other logos).
Important: Reboot after install! For testing purposes, the trial version is enough, at least if there is a solution for Shrew upcoming in a few weeks, hopefully.
Of course, the settings of VPN networks are quite user-specific, but usually you can manually apply your Shrew settings almost 1:1, the input namings are nearly similar; e.g. start with the connection wizard and then customize your settings according to the Shrew properties.
I would like just 1 setting to mention which is not enabled by default in Shrew, which first caused a connection abort in my case: “PFS” has to be disabled, otherwise errors like “P2 proposal mismatch”, “NO MATCHING IPSEC PROPOSAL”, “NO_PROPOSAL_CHOSEN” or similar appear.