After upgrading to Ubuntu 11.10 (Oneiric Ocelot), some VPN connection using Shrew (2.1.7) times out. Nevertheless, Shrew 2.1.5 still works under Ubuntu 11.10. The challenge is to uninstall version 2.1.7 and install version 2.1.5.  This can be done in a few simple steps.

1) Download the proper ike 2.1.5 packages for your version of Ubuntu.

32 bits:

http://packages.ubuntu.com/natty/i386/ike/download
http://packages.ubuntu.com/natty/i386/ike-qtgui/download

64 bits:

http://packages.ubuntu.com/natty/amd64/ike-qtgui/download
http://packages.ubuntu.com/natty/amd64/ike/download

2) Uninstall version 2.1.7.  Open a shell window and issue this command:

sudo apt-get purge ike ike-qtgui

3) In the same shell window, move to your download directory and issue these commands to install version 2.1.5

32 bits:

sudo dpkg -i ike_2.1.5+dfsg-2_i386.deb
sudo dpkg -i ike-qtgui_2.1.5+dfsg-2_i386.deb

64 bits:

sudo dpkg -i ike_2.1.5+dfsg-2_amd64.deb
sudo dpkg -i ike-qtgui_2.1.5+dfsg-2_amd64.deb