Install vpnc on MacOS Sierra

Update: 3.4.2017. this no longer works since homebrew/boneyard got obsoleted/deleted today.

If you try to install Cisco VPN concentrator client (vpnc) today, chances are you won’t be able to since it was removed from regular homebrew formulae.

brew install vpnc
Error: No available formula with the name "vpncc"
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching taps...
Error: No formulae found in taps.

However you can still install it from archive of homebrew formulae (boneyard):

brew cask install tuntap
brew install homebrew/boneyard/vpnc

Be aware that this version of vpnc requires tuntap installed, also, it installs all this as dependencies:

brew deps vpnc
gmp
gnutls
libffi
libgcrypt
libgpg-error
libtasn1
libunistring
nettle
p11-kit

This will install last available, rather old vpnc version 0.5.3 dating back in 2006.

I found a new and modified version of vpnc on github modified for xnu (OS X 10.6+) and utun support so tuntap is not required. Unfortunately it is not yet in brew as formulae. However if you install all above dependencies, you will be able to build it easily your self:

git clone https://github.com/breiter/vpnc.git
cd vpnc
make
sudo make install

This will install vpnc version 0.5.3-xnu-2015-07-03.

Both vpnc versions expect configuration to be present in

/usr/local/etc/vpnc