Internet server monitoring is much wider than website monitoring

Website monitoring

Website monitoring is the process of testing and verifying that end-users can interact with a website or web application. Website monitoring is often used by businesses to ensure that their sites are live and responding....

. Monitoring a web server means that the server owner always knows if one or all of his services go down. Web server monitoring may be internal, i.e. web server

Web server

Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....

 software checks its status and notifies the owner if some services go down, and external, i.e. some web server monitoring companies check the services status with a certain frequency. External monitoring is much more reliable, as it keeps on working when the server completely goes down.

Various protocols

Web server monitoring service can check HTTP pages, HTTPS

Https

Hypertext Transfer Protocol Secure is a combination of the Hypertext Transfer Protocol with SSL/TLS protocol to provide encrypted communication and secure identification of a network web server...

, FTP, SMTP, POP3, IMAP, DNS

Domain name system

The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...

, SSH

Secure Shell

Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...

, Telnet

TELNET

Telnet is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communications facility using a virtual terminal connection...

, SSL, TCP

Transmission Control Protocol

The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...

, PING

Ping

Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol network and to measure the round-trip time for messages sent from the originating host to a destination computer...

 and a range of other protocols with great variety of check intervals from every 4 hours to every one minute. Typically, most website monitoring services test a server anywhere between once-per hour to once-per-minute.

Web server monitoring process

When monitoring a web server for potential problems, an external web monitoring service checks a number of parameters. First of all, it monitors for a proper HTTP return code. By HTTP specifications RFC 2616, any web server returns several HTTP codes. Analysis of the HTTP codes is the fastest way to determine the current status of the monitored web server.

Notification

As the information brought by web server monitoring services is in most cases urgent and may be of crucial importance, various notification methods may be used: e-mail

E-mail

Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...

, land-line and cell phones, SMS

SMS

SMS is a form of text messaging communication on phones and mobile phones. The terms SMS or sms may also refer to:- Computer hardware :...

, fax

Fax

Fax , sometimes called telecopying, is the telephonic transmission of scanned printed material , normally to a telephone number connected to a printer or other output device...

, pagers, etc.