subject: What Is A Mail Server? [print this page] A Mail Server, also known as an email server is like a virtual post office in your computer. It consists of a storage area where emails can be stored for local users. It has a set of user defined rules that decides how the server should react to the destination of a specific message. It also houses a database of user accounts which the server recognizes. It is made up of communication modules which handle the transfer of messages to and from other mail servers and email clients.
An Email Client or Email pr helps a user to send and receive emails with the help of mail servers. There are many types of mail clients with different features.
When an email is sent, the authors ISP mail server is contacted to pass on the message. The mail server is normally namedmail.[isp].com or it might be named after the Send Mail Transfer Protocol, smtp.[isp].com. The server scans the messages headers for addressing the information. These headers are usually not visible in the email client. If they have to be visible, the user has to configure the program to show the headers.
The email message is sent to the address. This might need the message to be sent through several routers. Routers are computers that receive network data and re-route it through the shortest path. If nothing is wrong, the email will reach its destination within seconds or minutes of it being sent.
Once the mail reaches its destination, it is stored in a virtual mailbox. It will be there until the receiver uses his/her mailbox to check for new mail. To do so the mail box needs to contact its receiving mail server. It is called as the POP3 mail server (for Post Office Protocol 3) as in pop3.[isp].com, or simply mail.[isp].com. When the program asks the mail server for any mail, it checks the server for any new mail for that user. If a new mail is found, it is transferred to the user as requested. Mail servers located on public websites work in the same basic manner as ISP mail servers.
Due to the large amount of unwanted emails called Spam, some mail servers are configured to block certain IP addresses that are known to send spam. An IP Address is a unique numerical address. It is different from the replying address. Spam Filters operate at the level of the email servers and also at the level of email programs that offer similar features. Email programs can also filter mails into folders as they are received. It normally sends a command to the mail server to delete the messages from the server that are already collected.
In another effort to stop Spam, mail servers have filters that stop users from sending duplicate messages to multiple addresses. However, mailing lists are an exception to this. They have a different software that identifies the traffic as legitimate.
