netcheck

netcheck monitors Internet availability and, if needed, switches to alternative connections in a predefined order. This program provides more control over the gateway connection than NetworkManager alone provides.

netcheck is licensed under the GNU GPLv3. All source code commits prior to the public release are also retroactively licensed under the GNU GPLv3.

This software is still in beta and may not be ready for use in a production environment.

Bug fixes are welcome!

Prerequisites

This software is currently only supported on Ubuntu 18.04.

Currently, the only supported method for installation of this project is building and installing a Debian package. The rest of these instructions make the following assumptions:

• You are familiar with using a Linux terminal.
• You are somewhat familiar with using debuild.
• You are familiar with using git and GitHub.
• debhelper and devscripts are installed on your build server.
• You are familiar with GnuPG (for deb signing).

Parkbench Dependencies

netcheck depends on one other Parkbench package, which must be installed first:

• parkbench-common

Steps to Build and Install

1. Clone the repository and checkout the latest release tag. (Do not build against the master branch. The master branch might not be stable.)
2. Run debuild in the project root directory to build the package.
3. Run apt install /path/to/package.deb to install the package. The daemon will attempt to start and fail. (This is expected.)

Post-Install configuration

Configuring NetworkManager

1. Add any network connections you want Netcheck to manage with nmcli con add.
2. Set all network connections managed by Netcheck to not auto-connect with nmcli con mod connection-name connection.autoconnect no.

Configuring Netcheck

Since running netcheck as a non-root user is more complex than with other Parkbench applications, you have the option of running netcheck as both a root and non-root user. In either case, you must do the following:

1. Copy or rename the example configuration file /etc/netcheck/netcheck.conf.example to /etc/netcheck/netcheck.conf.
2. Change the ownership and permissions of the configuration file:

   chown root:netcheck /etc/netcheck/netcheck.conf
   chmod u=rw,g=r,o= /etc/netcheck/netcheck.conf

3. Edit the /etc/netcheck/netcheck.conf file to enter the connection IDs, nameservers, and queryable domains. Other settings can also be modified.
4. To ease system maintenance, add netcheck as a supplemental group to administrative users. Doing this will allow these users to view netcheck log files.

If you are running netcheck as a root user, please do the following:

1. Modify the configuration file to set 'run_as_root' to 'True'.

If you are running netcheck as a non-root user, please do the following:

1. Verify the configuration file has 'run_as_root' set to 'False'.
2. Run mkdir -p /etc/dbus-1/system.d/.
3. Replace /etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf with a copy of /usr/share/netcheck/etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf. This change denies access to NetworkManager except for users root and netcheck.
4. Run mkdir -p /etc/NetworkManager/conf.d/.
5. Copy /usr/share/netcheck/etc/NetworkManager/conf.d/netcheck-auth-polkit-off.conf to /etc/NetworkManager/conf.d/. This disables NetworkManager's polkit authentication.
6. If your system is configured for unattended-upgrades (recommended), copy /usr/share/netcheck/etc/apt/apt.conf.d/99-netcheck-unattended-upgrades to /etc/apt/apt.conf.d/. This forces automatic-upgrades (and apt) to keep local modifications of configuration files.

Once the configuration is complete, restart NetworkManager with systemctl restart NetworkManager and then restart netcheck with systemctl restart netcheck. If the above steps were followed correctly, the service will start successfully.

Updates

Updates may change configuration file options. If a configuration file already exists, check that it has all of the required options from the current example file.

Known Errors and Limitations

• IPv4 and IPv6 networks do not work well together.
• Captive portal login pages typically trick netcheck into thinking it has access to the Internet.