Install Oracle's OpenConnect VPN on Ubuntu 16.04 LTS

Information retrieved at the address: http://tomtomtom.org/networkmanager-openconnect/

It worked on the first try on my machine.

We remove unusable packages:

sudo apt-get purge network-manager-openconnect network-manager-openconnect-gnome

We compile the dependencies:

sudo apt-get build-dep network-manager-openconnect

The sources in apt must be active:

sudo sed -i s/#deb-src/deb-src/g /etc/apt/sources.list

We install the new dependencies:

sudo apt-get install libnm-dev

We retrieve the source code:

wget http://ftp.gnome.org/pub/GNOME/sources/NetworkManager-openconnect/1.1/NetworkManager-openconnect-1.1.93.tar.xz

We go to the directory:

cd NetworkManager-openconnect-1.1.93

We launch the configure:

./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --libexecdir=/usr/lib/NetworkManager/ --enable-more-warnings=yes --disable-static

We compile:

make

We install:

sudo make install

We install openconnect:

sudo apt-get install openconnect

We compile the package with checkinstall:

sudo checkinstall

We add a system user:

sudo adduser --system --quiet --home /var/lib/NetworkManager --no-create-home --gecos "NetworkManager OpenConnect plugin" --group nm-openconnect}

And we restart.

Version context

This procedure describes the software and the environment available at the time of its publication. The packages, interfaces, and repositories mentioned may have changed or disappeared; first check the system version and its support level.

cat /etc/os-release
uname -r

Work on a backup or a snapshot, note every modified file, and prepare for rollback. For a current workstation or server, prefer signed packages from officially supported repositories.

Reference: official Ubuntu lifecycle.