Category Linux

2 Ways to Generate CSR with OpenSSL Command

1. What is CSR? A Certificate Signing Request (CSR) is a block of encoded text generated on a server that contains a request for a digital certificate (SSL/TLS) from a Certificate Authority (CA). The CSR carries your public key and…

Understanding X509 Certificate with Openssl Command

X.509 is a standard format for public key certificates, digital documents that securely associate cryptographic key pairs with identities such as websites, individuals, or organizations. It can be used for authenticated and encrypted web browsing, signed and encrypted email etc.…

Check SSL Certificate with OpenSSL in Linux

OpenSSL is an open-source command-line tool that is commonly used to generate private keys, create CSRs, install our SSL/TLS certificate, and identify certificate information. This quick reference can help us understand the most common OpenSSL commands and how to use…

Understanding ICMP Packets with Examples

Internet Control Message Protocol (ICMP), described in RFC 792 and part of the TCP/IP protocol stack, is an error reporting and control-based protocol used between network devices. ICMP messages are encapsulated into IP datagrams, which are then encapsulated into an…

6 Useful Makefile Examples

A makefile is a special file used to execute a set of actions. The most important purpose is the compilation of programs. Make is a dedicated tool to parse makefiles. Most open-source projects use make to compile a final executable…

Exploring ICMP with Examples

Internet Control Message Protocol (ICMP) is a network layer protocol that serves the purpose of error reporting and network path diagnostic functions. The Ping and Traceroute utility tools leverage ICMP messages for fault detection and isolation. ICMP messages are sent…

2 Ways to Check DNS TTL

DNS TTL, or time to live, is the element of a DNS record that tells the requester how long the record is valid. If the TTL for our DNS record is set to 24 hours, a browser has will continue…