Domain Name Service (DNS) As we covered in our networking course here, in order to send your message to a destination over a routed infrastructure, you need to encapsulate your message into a TCP/IP Layer-3 header. We have also covered that headers include source and destination addresses. In case of Layer-3 with TCP/IP model, we […]
tcpdump tcpdump is a text-based network sniffer. Let’s capture some traffic. We have used switch -i to indicate the interface on Kali Linux which we want to sniff on. Then we have specified our filer to match the traffic. If we don’t specify any filter, we capture all the traffic passing through that interface. The […]
hostnamectl and timedatectl To query and change the system hostname and related settings use hostnamectl command. timedatectl may be used to query and change the system clock and its settings, and enable or disable time synchronization services. ip vs ifconfig Ethernet networks are called ethx (old fashion) or things like enp0s25 (nowadays). Traditionally, ifconfig was the tool to configure […]
Netcat (nc) Netcad is installed by default on your Kali Linux. It is according to its man page is TCP/IP swiss army knife. It is a simple unix utility which reads and writes data across network connections, using TCP or UDP protocol. Netcat can run in client or server mode. Netcat in client mode In […]
wget wget is a utility for download of files from the Web. It supports HTTP, HTTPS, and FTP protocols. curl curl is a tool for transferring data from or to a server. It supports these protocols. Switch -o along with a string saves the file under the name of that string. As an exercise download […]
process status (ps) The command ps lists processes system-wide. This is one of your main tools to understand what software is running on the system. The main switches are: e to select all processes f to display full format listing (UID, PID, etc.) l to display in long format Finding your SSH process in the […]
Regular Expressions A Regular Expression (regex) is a text string which describes a pattern to find text. You can visit https://www.regular-expressions.info/tutorial.html to learn more about Regular Expressions. However, I will teach you the minimum you need to take from this course. Literal Characters Consider This is a test. sentence. Consider the most basic regular expression […]
At this point, I prefer to present my networking students a practical tool which Floods CAM Table of a Cisco Catalyst switch. It is unrelated to the previous and next posts. macof The command macof is the tool with which we are going to flood a LAN switch (In our example a Cisco Catalyst switch) […]
Stream, Piping, and Redirecting On a Unix-like system, the shell uses streams (a list of characters) for input and output: Stream Name Comment File Descriptor Standard Input (STDIN) provides input to commands 0 Standard Input (STDOUT) displays output from commands 1 Standard Input (STDERR) displays error output from commands 2 Streams in CLI Redirection They […]
find The find command – which is the most complex and powerful in this category – searches for files in a directory hierarchy. Its capabilities go beyond a simple file search. You can search by file age, timestamp, permissions, size, owner, and many more. Look at these: find / – At minimum, find gets a path to […]
Elissa Garlin
Think of a news blog that’s filled with content hourly on the day of going live.