This post describes how to see TCP connection establishment and termination as packets using tcpdump on linux. Preparing Install the following commands on our linux. tcpdump nc telnet netstat Start a TCP connection establishment Start TCP connection using nc command with l,k option. Open another terminal and verify 12345 port is listening using netstat command. …

In networking, a port is a virtual place on a machine that is open to connections from other machines. Every networked computer has a standard number of ports, and each port is reserved for certain types of communication. Think of ports for ships in a harbor: each shipping port is numbered, and different kinds of …

DNS propagation is the time for DNS record updates to take effect on all servers. DNS Changes are not instant because nameservers cache domain record information for a specific duration before refreshing.  Some users may still be served a cached version of our site until all servers have completed propagation. DNS Propagation Time So, how …

CrazyGames is a free online games website with more than 10 million active users monthly. The company was founded in 2014 by Tomas and Raf Mertens and has grown to 9 people. The platform features games ranging from 3D shooters to puzzle games. The most popular categories are driving games, clicker games, minecraft games, stickman …

Reverse DNS lookup, also known as rDNS, is used to determine or resolve the IP address associated with the domain name. It is simply an entry that resolves an IP address back to a hostname. It is also called PTR record in DNS. Purpose of reverse DNS lookups Reverse DNS lookups are commonly used by …

DNS PRT record is short for pointer record. It is one of the common Domain Name System (DNS) records. It resolves an IP address to a domain or hostname. It is also called DNS reverse record. The following commands can be used to check PTR record in Linux. dig -x 8.8.8.8 nslookup 8.8.8.8   What …

DNS MX record is short for mail exchange. It is used to direct email to a mail server. The MX record indicates how email messages should be routed when we send out an email. The best way is to check dns MX record in Linux is using the dig command.  For example: dig domain.com mx …

DNS A record maps a domain name to the IP address (Version 4) of the server hosting the domain. The “A” stands for “address”. DNS A record indicates the IP address of a given domain. DNS A record is the most fundamental type of DNS record. It is one of the primary records used in …

A DNS, or Domain Name Server, is what helps translate human-friendly URLs into computer-friendly IP addresses. This is what enables our devices to connect to the internet and access the content we want to see. When people change their DNS, it’s usually to enhance either performance, security or both! Below, we’ll take a look at …

The OpenSSL s_client command is a helpful test client for troubleshooting remote SSL or TLS connections. This post covers various examples of testing SSL connections with different ciphers, TLS versions, and SSL server certificate analysis. OpenSSL s_client connect openssl s_client -connect example.com:443 Use the openssl s_client -connect flag to display diagnostic information about the SSL …