netwyman

A mail server (or email server) is a computer system that sends and receives   email . In many cases,   web servers   and mail servers are combined in a single machine. However, large   ISPs   and public email services (such as Gmail and Hotmail) may use dedicated hardware for sending and receiving email. In order for a computer system to function as a mail server, it must include mail server   software . This software allows the system administrator to create and manage email accounts for any   domains   hosted on the server. For example, if the server hosts the   domain name   "techterms.com," it can provide email accounts ending in "@techterms.com." Mail servers send and receive email using standard email   protocols . For example, the   SMTP   protocol sends messages and handles outgoing mail requests. The   IMAP   and   POP3   protocols receive messages and are used to process incoming mail...

Access control list (ACL) is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects or you can say for each rule we have two conditions and that is Permit or Deny. Access List Access-list (ACL) is a set of rules defined for controlling the network traffic and reducing network attack. ACLs are used to filter traffic based on the set of rules defined for the incoming or out going of the network. Types of ACL: Standard Access List: Extended Access List: Standard Access List- These are the Access-list which are made using the source IP address only. These ACLs permit or deny the entire protocol suite. They don’t distinguish between the IP traffic such as TCP, UDP, Https etc. By using numbers 1-99 or 1300-1999, router will understand it as a standard ACL and the specified address as source IP address. Extended Access List- These are the ACL which uses b...