Book Image

Learning RHEL Networking

By : Andrew Mallett, Adam Miller
Book Image

Learning RHEL Networking

By: Andrew Mallett, Adam Miller

Overview of this book

Table of Contents (18 chapters)
Learning RHEL Networking
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Firewall rules using services


When we think of firewalls, we think of allowing or denial of access to ports. The use of service XML files can ease the port management with one service, perhaps listing multiple ports. The other point to take note of is that firewalld daemon's default policy is to deny access, so any access needed has to be explicitly granted to a port associated with a service. To list services that have been allowed on the default zone, we can simply use the --list-services option, as shown in the following example:

# firewall-cmd --list-services

Similarly, we can gain access to services allowed in a specific zone by including the --zone= option. This can be seen in the following example:

# firewall-cmd --zone=home --list-services

The output from this command is shown in the following screenshot. It lists services associated with the home zone:

As you start enabling services, you can easily allow a predefined service through a zone. Predefined services are listed as XML files...