Firewall


Table of Contents
1. Firewall
1.1. Interfaces
1.2. Ports/Services
1.3. Manual operation
1.3.1. Enable/disable firewall
1.3.2. Modifying services/ports
1.3.3. Modifying the zone of interfaces

1. Firewall

Firewall is a network security system that controls the incoming and outgoing network traffic. Keeping a firewall enabled and properly configured reduces risk of security threat from the Internet.

The operation of the firewall in Plinth web interface of FreedomBox is automatic. When you enable a service it is automatically permitted in the firewall and when you disable a service it is automatically disabled in the firewall. For services which are enabled by default on FreedomBox, firewall ports are also enabled by default during the first run process.

Firewall management in FreedomBox is done using FirewallD.


1.1. Interfaces

Each interface is needs to be assigned to one (and only one) zone. Whatever rules are in effect for a zone, those rules start to apply for that interface. For example, if HTTP traffic is allowed in a particular zone, then web requests will be accepted on all the addresses configured for all the interfaces assigned to that zone.

There are primarily two firewall zones used. The internal zone is meant for services that are provided to all machines on the local network. This may include services such as streaming media and simple file sharing. The external zone is meant for services that are provided publicly on the Internet. This may include services such as blog, website, email web client etc.

For details on how network interfaces are configured by default, see the Networks section.


1.2. Ports/Services

The following table attempts to document the ports, services and their default statuses in FreedomBox. If you find this page outdated, see the Plinth source for lib/freedombox/first-run.d/90_firewall and Firewall status page in Plinth UI.

Service

Port

External

Enabled by default

Status shown in Plinth

Managed by Plinth

Minetest

30000/udp

XMPP Client

5222/tcp

XMPP Server

5269/tcp

XMPP Bosh

5280/tcp

NTP

123/udp

Plinth

443/tcp

Quassel

4242/tcp

SIP

5060/tcp

SIP

5060/udp

SIP-TLS

5061/tcp

SIP-TLS

5061/udp

RTP

1024-65535/udp

SSH

22/tcp

mDNS

5353/udp

Tor (Socks)

9050/tcp

Obfsproxy

<random>/tcp

OpenVPN

1194/udp

Mumble

64378/tcp

Mumble

64378/udp

Privoxy

8118/tcp

JSXC

80/tcp

JSXC

443/tcp

DNS

53/tcp

DNS

53/tdp

DHCP

67/udp

Bootp

67/tcp

Bootp

67/udp

Bootp

68/tcp

Bootp

68/udp

LDAP

389/tcp

LDAPS

636/tcp


1.3. Manual operation

See FirewallD documentation for more information on the basic concepts and comprehensive documentation.


1.3.1. Enable/disable firewall

To disable firewall

service firewalld stop

or with systemd

systemctl stop firewalld

To re-enable firewall

service firewalld start

or with systemd

systemctl start firewalld

1.3.2. Modifying services/ports

You can manually add or remove a service from a zone.

To see list of services enabled:

firewall-cmd --zone=<zone> --list-services

Example:

firewall-cmd --zone=internal --list-services

To see list of ports enabled:

firewall-cmd --zone=<zone> --list-ports

Example:

firewall-cmd --zone=internal --list-ports

To remove a service from a zone:

firewall-cmd --zone=<zone> --remove-service=<service>
firewall-cmd --permanent --zone=<zone> --remove-service=<interface>

Example:

firewall-cmd --zone=internal --remove-service=xmpp-bosh
firewall-cmd --permanent --zone=internal --remove-service=xmpp-bosh

To remove a port from a zone:

firewall-cmd --zone=internal --remove-port=<port>/<protocol>
firewall-cmd --permanent --zone=internal --remove-port=<port>/<protocol>

Example:

firewall-cmd --zone=internal --remove-port=5353/udp
firewall-cmd --permanent --zone=internal --remove-port=5353/udp

To add a service to a zone:

firewall-cmd --zone=<zone> --add-service=<service>
firewall-cmd --permanent --zone=<zone> --add-service=<interface>

Example:

firewall-cmd --zone=internal --add-service=xmpp-bosh
firewall-cmd --permanent --zone=internal --add-service=xmpp-bosh

To add a port to a zone:

firewall-cmd --zone=internal --add-port=<port>/<protocol>
firewall-cmd --permanent --zone=internal --add-port=<port>/<protocol>

Example:

firewall-cmd --zone=internal --add-port=5353/udp
firewall-cmd --permanent --zone=internal --add-port=5353/udp

1.3.3. Modifying the zone of interfaces

You can manually change the assignment of zones of each interfaces after they have been autuomatically assigned by the first boot process.

To see current assignment of interfaces to zones:

firewall-cmd --list-all-zones

To remove an interface from a zone:

firewall-cmd --zone=<zone> --remove-interface=<interface>
firewall-cmd --permanent --zone=<zone> --remove-interface=<interface>

Example:

firewall-cmd --zone=external --remove-interface=eth0
firewall-cmd --permanent --zone=external --remove-interface=eth0

To add an interface to a zone:

firewall-cmd --zone=<zone> --add-interface=<interface>
firewall-cmd --permanent --zone=<zone> --add-interface=<interface>

Example:

firewall-cmd --zone=internal --add-interface=eth0
firewall-cmd --permanent --zone=internal --add-interface=eth0