TCP Sequence Number is a 4-byte field in the TCP header that indicates the first byte of the outgoing segment. It helps to keep track of how much data has been transferred and received. The TCP Sequence Number field is always set, even when there is no data in the segment. For example, the sequence …
Linux
TCP socket is a fundamental concept in the operation of TCP/IP application world. We will deep dive into the details of how the TCP socket works. Network Socket For example, if we have a website running on IP address 100.1.1.1, the socket corresponding to the HTTP server for that site would be 100.1.1.1:80. Sockets are …
tcpdump is a powerful command-line network packet analyzer used for network troubleshooting and analysis. To capture UDP packets using tcpdump, you can use specific filtering options to narrow down the traffic you want to capture. UDP Protocol UDP is a connectionless protocol. This means that there is no three-way handshake carried out before data is …
Tcpdump is a CLI tool to capture raw network packets. It is very useful for various forms of network troubleshooting. We will learn how to filter packets by port in tcpdump command. TCP and UDP Ports Our system uses ports to communicate with other devices on a network. Each port is associated with a specific …
Portmap is a service that converts RPC program numbers into protocol port numbers. It must be running in order to make RPC calls. Portmap makes the dynamic binding of remote programs possible. NFSv3 is based on portmap. We will dive into this today. How Portmap works? The portmap service maps RPC service and version numbers …
The rpcbind is a utility that converts RPC program numbers into universal addresses. It must be running on the host to be able to make RPC calls. We will dive into RPCbind today to see how it works. Understanding RPC Remote Procedure Call (RPC) is an inter-process communication technique to allow client and server software …
Network File Sharing (NFS) is a protocol that allows us to share directories and files with other Linux clients over a network. The ports for NFS are confusing for many people. We will deep dive into this today. NFSv3 Port NFSv4 Port NFSv3 Port NFSv3 and NFSv2 include portmapper, nfsd, and other NFS services like …
Bash For loop is used to execute a series of commands until a particular condition becomes false. Bash for loop in one line is very handy for Linux admins. Bash for loop in one line is a control structure that allows you to repeat a certain set of commands multiple times. The syntax is: for …
PSH and ACK are tcp flags in the TCP protocol. These TCP flags are ways for TCP to communicate between clients and servers. PSH (push) flag indicates that the incoming data should be passed on directly to the application instead of getting buffered. ACK (acknowledgment) flag is used to confirm that the data packets have …
In this Linux command line cheat sheet, we will learn: Basic Linux Commands File management user management Linux Commands Programing Linux Commands Job management Filesystem management Linux commands Process management Linux Commands Shortcuts network System Info Searching File Permission Basic Linux Commands cat – Joins and displays files cp – Copies files cpio – …