Network articles

Last change: 2025-01-06

Looking for all DNS requests made on a Linux system? Tools like dnstop, firejail, and tcpdump can help to find what is being queried.

Last change: 2025-01-10

The Linux command netcap shows an overview of running processes and what capabilities they have. This applies to those that are using active network sockets.

Last change: 2025-01-06

Everything related to iptables, one of the firewall solutions on Linux. Learn how to configure, tune, and monitor iptables.

Last change: 2025-01-06

This section covers articles related to the Linux nftables module, the replacement for iptables. Learn how to configure, tune, and monitor nftables.

Last change: 2025-01-06

The kernel has a wide range of network settings. Learn about the sysctl command and the values related to the network class.

Last change: 2025-01-06

The sysctl key net.ipv4.ip_forward key is used to define IP forwarding of IPv4 network packets. Learn about the possible values of this key and their meaning.

Last change: 2025-01-06

Show IP address information on Linux with the help of the ip command. Learn which subcommands to use to query the relevant details.

Last change: 2025-01-06

Show the IP address of your internet connection using the dig or the curl command. Learn which options can be used to find out this information.

Last change: 2025-01-06

Find the active DNS server being used by reviewing the network configuration, including common commands to query this information.

Last change: 2025-01-06

Linux has in-depth details, including about network connections. Show the number of open connections using the ss command on Linux.

Last change: 2025-01-10

The command iftop shows ongoing bandwidth usage on one or more network interfaces and is a great tool for troubleshooting network issues.

Last change: 2025-01-06

Show the bandwidth usage and active connections by using the iftop tool on Linux. Learn how to use the tool to quickly find out this information.

Last change: 2025-01-06

Linux with systemd might doing DNS resolving using its resolver daemon. Learn how to inspect and clear the DNS cache when using the systemd resolver daemon.

Last change: 2025-01-10

The command resolvectl provides details about systemd-resolved. Discover the available options for the name resolution daemon on Linux systems.

Last change: 2025-01-06

This section has all articles and information about troubleshooting network performance issues and monitoring network statistics.

Last change: 2025-01-06

Show counters related to the TCP connections by using the nstat command. This small utility will quickly retrieve the related statistics and display them.

Last change: 2025-01-06

Show the network link details using the ip command to find out if a network has errors or dropped packets on a Linux system.

Last change: 2025-01-06

Use the network routing table to discover the default gateway on a Linux system. Here is how to use the ip command to achieve this

Last change: 2025-01-06

TCP or UDP ports can already be in use when starting up a service. Find out which process opened an UDP or TCP port on Linux by using the ss command.

Last change: 2025-01-06

Show which UDP/TCP ports are opened on a Linux system, including the related process. Use the ss tool to see more details about these sockets.

Last change: 2025-01-06

Frequently asked questions about networking, such as DNS, IP configuration, TCP/UDP details, and more.

Last change: 2025-01-06

Learn how to query the Time To Live (TTL) for a DNS record by using the dig tool on a Linux systems, including any relevant options.

Last change: 2025-01-06

BPFILTER is one of the newer features to provide traffic filtering. Learn how it works and why it may replace iptables as the firewall on Linux systems.

Last change: 2025-01-06

The replacement of iptables is known as nftables. In this article, we learn to install nftables and configure it, to secure your Linux systems.

Last change: 2025-01-06

Also wondering what some files are used for on Linux systems? In this article we have a look at the /etc/networks file and show some configuration.

Last change: 2025-01-06

An overview of the differences between firewall technologies iptables and nftables. We highlight the major differences like simplicity and management.

Last change: 2025-01-06

Extensive guide to help you secure your IPv6 configuration on Linux. From initial set-up to hardening the kernel with sysctl.

Last change: 2025-01-06

Show the available network interfaces and information on Linux with the right tools. We cover common replacements for iptables and netstat, with examples.

Last change: 2025-01-06

Seeing the 'address in use' error or need to find out which process is listening to a particular port on Linux? Here are the tools to find out!

Last change: 2025-01-06

Filtering ARP traffic is easy with the arptables utility. In this article we look at the possibilities of arptables and provides example of using it.

Last change: 2025-01-06

Clearing the ARP cache on Linux is easy with the arp or ip utility. This blog post will help you to clear the cache with examples for both utilities.

Last change: 2025-01-06

This article describes how to audit the network configuration of Unix and Linux based systems, with useful tips for auditors and system administrators.