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David Cao

David is a Cloud & DevOps Enthusiast. He has years of experience as a Linux engineer. He had working experience in AMD, EMC. He likes Linux, Python, bash, and more. He is a technical blogger and a Software Engineer. He enjoys sharing his learning and contributing to open-source.

A Fully Qualified Domain Name (FQDN) is the complete domain name of a specific computer, or host, online. A FQDN gives its precise location in the hierarchy of DNS records. It is the complete address for websites and other computers and entities accessing the Internet resolving to the root domain. An FQDN is comprised of …

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To fix “to use the the ‘ssh’ connection type with passwords, you must install the sshpass program”, we need to install sshpass package in our ansible control machine. What is sshpass? Sshpass is a utility that allows you to store and use your SSH password in a secure way. Sshpass is typically used in conjunction …

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An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates the identity of a website and encrypts information sent to the server using SSL technology. Encryption is the process of scrambling data into an undecipherable format that can only be returned to a readable format with the proper decryption key. How to choose …

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MX Lookup means to perform the MX Record Lookup in the DNS. It is used to check the MX Record to find the internal & external mail servers for a particular domain. MX Record The DNS MX record is a DNS record that routes the email to the correct email server. The MX record tells …

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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. …

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