DevOps :: DevSecOps

Q.Explain DKIM? Ans: DomainKeys Identified Mail (DKIM) is a method for associating a domain name to an email message, thereby allowing a person, role, or organization to claim some responsibility for the message.The organization is a handler of the message, either as its originator or as an intermediary.Technically DKIM provides a method for validating a domain name identity that is associated with a message through cryptographic authentication.DKIM attaches a new domain name identifier to a message and uses cryptographic techniques to validate authorization for its presence. The identifier is independent of any other identifier in the message, such in the author's From: field. DKIM defines an authentication mechanism for email, using:      a.A domain name identifier      b.Public-key cryptography      c.A DNS-based public key publishing service. An agent in the message transit path can sign the message content and selected header fields. The signature information is placed into

What is Nagios and how it Works ?. Nagios is an open source System and Network Monitoring application.Nagios runs on a server, usually as a daemon or service. Nagios periodically run plugins residing (usually) on the same server, they contact (PING etc.) hosts and servers on your network or on the Internet. You can also have information sent to Nagios. You then view the status information using the web interface. You can also receive email or SMS notifications if something happens. Event Handlers can also be configured to "act" if something happens.The Nagios daemon behaves like a scheduler that runs certain scripts at certain moments. It stores the results of those scripts and will run other scripts if these results change. All these scripts are, of course, the scripts from the Nagios plug-in project or are scripts that you have created. Explain Main Configuration file and its location? Resource File  : It is used to store sensitive information like username,passwor