Linux find command is a powerful tool that can be used to locate and manage files and directories based on a wide range of search criteria. This means that we can provide it with a set of directories (or files) or filters, and it will apply appropriate actions to them. This post covers 20 advanced …

Dig is a very powerful Linux command to query DNS in Linux. We will dive into the dig command output today. The dig command is a DNS lookup utility that can be used to troubleshoot DNS issues in Linux. It can also be used to query DNS records. The dig command can be used to …

DNS port is confusing for many people. In this article, we’ll describe how DNS works, and what DNS port numbers are used for DNS protocol. Port Usage TCP port 53: Large DNS responses (TCP is used when the DNS response exceeds the maximum size that can be accommodated in a single UDP packet.) DNS zone …

TCP is defined as a connection-oriented and reliable protocol. We will check out how TCP connection works in this article. How TCP Connection Works? TCP allows for the transmission of information in both directions. This means that computer systems that communicate over TCP can send and receive data at the same time, similar to a …

TCP vs UDP – Acronym TCP: Transmission Control Protocol UDP: User Datagram Protocol TCP vs UDP – Connection TCP: Is a connection-oriented protocol. This means the system is able to send and receive data. UDP: Is a connection-less protocol. This means the service can only send packets.   TCP vs UDP – Protocols TCP: HTTP, …

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 …

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 can be used to capture network packets for many protocols like UDP, TCP, ICMP, etc. We are going to review how to filter UDP packets with tcpdump. UDP Protocol UDP is a connectionless protocol. This means that there is no three-way handshake carried out before data is transmitted. The sending device literally sends the …

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 …