dig can return cached responses because it caches the results of previous queries to improve performance. For the same reason the cache responses can come from the configured name servers. This is useful when you are querying the same domain multiple times, but it can be problematic when you need to check if a change […]
network
IPTables: Monitor Network Traffic in Real-Time
In a combination with a watch command an iptables can be used to monitor a network traffic in a real-time. This is especially useful for troubleshooting various network issues. Bellow you will find some examples of how to monitor the network traffic in a real-time using the iptables and watch commands.
TCPDump Examples – 30 Best Commands Ever!
tcpdump is a command-line network packet analyzing tool, that is absolutely essential for troubleshooting networking issues. It is used to display network packets transmitted over network interfaces connected to the system on which tcpdump is installed. tcpdump has a large set of flags and arguments used to specify various options, which can be pretty overwhelming […]
IPv6 Ping – How to Ping an IPv6 Address in Windows
An IPv6 is a preferred protocol over IPv4 in modern Windows and Linux systems. In Windows, you can ping IPv6 addresses using a standard ping command. If the ping command fails to ping the IPv6 address, it could be that the IPv6 protocol is disabled or it is not supported by your computer or the […]
IPv6 Ping – How to Ping an IPv6 Address in Linux
An IPv6 is a preferred protocol over IPv4 in modern Windows and Linux systems. In Linux, you can ping IPv6 addresses using a standard ping command as well as a special ping6 command. This short note shows how to ping the IPv6 addresses in Linux.
What Is My Router’s IP Address (Default Gateway)
A router is a device that communicates between the Internet (or public network) and the devices in a local network (or private network). A typical home router, that usually acts as a default gateway for the local devices, can be configured using a web-based configuration page that can be accessed from a web-browser if you […]
CIDR Notation – Explained & Examples
CIDR (Classless Inter-Domain Routing) notation is a compact method for specifying IP addresses and their routing suffixes.
Disable IPv6 on Linux – Ubuntu, Debian, CentOS
To disable IPv6 on Linux it is required to modify Linux kernel parameters. IPv6 can be temporary disabled at runtime, using sysctl command or it can be disabled permanently using either sysctl configuration file or the required kernel parameters can be passed at boot time using GRUB configuration. In this note i am showing how […]
169.254.0.0/16 – Disable ZEROCONF Route
You may notice that in your routing table you have a route 169.254.0.0/16. It is so called ZEROCONF route. Every time the system boots, the ZEROCONF route (169.254.0.0/16) is enabled and added to the routing table. And it is time to get rid of it.
Finding Active Computers in Local Network from Linux
Searching for Linux command that can list all IP addresses of devices connected to the network? Use nmap or ping commands to determine alive hosts in your local network. [nmap] Scan Network for Alive Computers Scan for active hosts on a network using nmap command: # Standard ICMP ping $ nmap -sn 192.168.1.0/24 Sample output: […]