Tcpdump is a CLI tool to capture raw network packets. This tcpdump cheat sheet covers all the basic and advanced options for tcpdump command. It is very useful for various forms of network troubleshooting. Purpose of Tcpdump This tool is mainly used for troubleshooting network problems. For example, if we can have a DNS query …
Linux
Tcpdump is a command-line packet analysis tool. We can use tcpdump to capture ssh traffic to troubleshoot connection issues and look for potential security issues on a network. What is SSH? What is the default port number for ssh? How to capture SSH traffic with Tcpdump? What is SSH? SSH, which stands for Secure …
Analyzing disk issues is an important task for Linux admins. Disk I/O bottlenecks can bring down applications. In this tutorial, we will learn how to check disk space usage, disk load usage, disk iops, disk latency. Hope this post can give you more ideas on how to troubleshoot disk problems. Check Disk Space Usage with …
Tcpdump is a very powerful Linux command to capture DNS packets. DNS is short for Domain Name System. It is a database that links meaningful names to a specific IP address. We can use tcpdump to filter DNS packets to learn more about how DNS works. What is DNS? Query DNS record on Linux Filter …
ICMP is a network layer protocol used by network devices to diagnose network communication issues. Tcpdump command on Linux can be used to capture network packets. We can use the following examples to capture ICMP and ICMPv6 packets with tcpdump command on Linux. What is ICMP? The Internet Control Message Protocol (ICMP) is a protocol …
Nethogs is a Linux command that allows us to view network usage of a running process in realtime. Nethogs sorts the output by process and network bandwidth usage. We can quickly find out which process is using more bandwidth. This is an important command when we troubleshoot network problems in realtime. How to install nethogs …
This article is part of the following series. 6 performance tools you should know in Linux 5 Ways to Check disk size in Linux 4 Ways to Check Disk Partition with Examples in Linux How I Fixed a disk performance issue in Minutes – A Step by Step Guide to Optimize Linux System Iotop …
Timeo is a timeout mount option in NFS mount. It is the timeout value that the NFS client uses to wait for a response before it retries an NFS request. Let’s dive into the details about what this timeout value means between NFS over TCP and NFS over UDP. Check this post to learn more …
If you’re a Linux system administrator, then you’re probably familiar with DNS, which is a critical component of networking. TCPdump is a powerful Linux command that can help you capture and filter network packets. With TCPdump, you can analyze DNS query traffic which gives you greater insights into how DNS works. In this article, we’ll …
Top is a very powerful command to periodically display a sorted list of system processes. The default sorting key is %CPU on Linux. Below we collect 3 ways to sort processes by memory. Understanding top command in Linux The top command in Linux is used to display information about the current running processes on your …