Useful protocols for a software tester

What web protocol is ?
When two or more computers communicate in Internet , they must have a common way in which to communicate. They use protocol to do it. Simply, protocol is an agreement by which two or more computers can communicate.

Transmission Control Protocol/Internet Protocol(TCP/IP) is set of Internet communication protocol. Transfer Control Protocol (TCP) breaks data into small pieces (called Packets) of no bigger than 1500 characters each. Each packet is inserted into different Internet Protocol (IP) “envelopes.” Each contains the address of the intended recipient and has the exact same header as all other envelopes. A router receives the packets and then determines the most efficient way to send the packets to the recipient. Upon arrival at their destination, TCP checks the data for corruption against the header included in each packet. If TCP finds a bad packet, it sends a request that the packet be re-transmitted. Numeric IP address( is a 32-bit address comprised of four 8-bit numbers (28) separated by periods. Each of the four numbers has a value between 0 and 255) works perfectly for web address However instead of IP Address, use of Uniform Resource Locator's (URLs) is in use because of it's user friendliness. So when a human types a URL into a browser, the request is sent to a Domain Name Server (DNS), which then translates the URL to an IP address understood by computers.

HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Whenever you surf the web, your browser will be sending HTTP request messages for HTML pages, images, scripts and styles sheets. Web servers handle these requests by returning response messages that contain the requested resource.
HTTP protocol is not suitable for use in a wide range of applications because it can be easily monitored and replayed. For example, someone using a network monitor can easily capture passwords used to access a banking web site. So, HTTP supports the use of several authentication mechanisms to control access to pages and other resources. HTTPs runs over an encrypted SSL session (HTTP over SSL (Secure Sockets Layer)) . So, if the website begins with https:// instead of http://, it is a secure site. Client and server need to create a shared secret key by using a public / private key handshake. Typically, HTTP data is sent over TCP/IP port 80, whereas SSL HTTP data is sent over port 443.
Web have a secure connection or not:
In Internet Explorer, you will see a lock icon in the Security Status bar. The Security Status bar is located on the right side of the Address bar. For example this web site is not secure. Security Status bar color is red. and there is certification error instead of lock sign.

This website is secured. It has white Security Status bar That means it has normal validation certificate and lock sign is there.

This website is secured. it has green Security Status bar . That means it has extended validation certificate.
Color in web status bar; What it means? Red The certificate is out of date, invalid, or has an error. For more information, see "About Certificate Errors" in Related Topics. Yellow The authenticity of the certificate or certification authority that issued it cannot be verified. This might indicate a problem with the certification authority's website. White The certificate has normal validation. This means that communication between your browser and the website is encrypted. The certification authority makes no assertion about the business practices of the website. Green The certificate uses extended validation. This means that communication between your browser and website is encrypted and that the certification authority has confirmed the website is owned or operated by a business that is legally organized under the jurisdiction shown in the certificate and on the Security Status bar. The certification authority makes no assertion about the business practices of the website.

File Transfer Protocol (FTP), a standard Internet protocol is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol HTTP which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol SMTP which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers.

Simple Object Access Protocol (SOAP) is a protocol that can be used for accessing the Web pages. SOAP is an XML based Object invocation Protocol. SOAP was developed for distributed applications to communicate through HTTP and firewalls. SOAP messages are independent of any operating system or protocol and may be transported using a variety of Internet protocols including SMTP, MIME, and HTTP 

Simple Mail Transfer Protocol, a protocol for sending email messages between servers. The messages can then be retrieved with an e-mail client using either POP or IMAP

Post Office Protocol, a protocol used to retrieve e-mail from a mail server to email client. POP stores your email on your computer in your email client (i.e. Thunderbird, Outlook, or whatever program you use to check email). When you check email, it is downloaded to your email client and removed from the mail server. This is why you can read your email when you're offline—because the email is actually on your computer you don't need an Internet connection to see it.


It is a protocol for accessing mail that is in mail server using an email client. IMAP keeps your email on the mail server so you can access it from multiple locations and with multiple email clients. For example, you can see the same email at home and at work. Likewise, you can see it in iCampus, Webmail, and Thunderbird.


SMTP uses the MIME protocol to send binary data across TCP/IP networks. The MIME protocol converts binary data to pure text.


TCP (a network protocols) is used for transmission of data from an application to the network. TCP is responsible for breaking data down into IP packets before they are sent, and for assembling the packets when they arrive. IP is responsible for the sending and receiving data packets over the Internet.

Is responsible for allocating the dynamic IP address to computer in a network. Dynamic Host Configuration Protocol (DHCP) is a standard protocol defined by RFC 1541 (which is superseded by RFC 2131) that allows a server to dynamically distribute IP addressing and configuration information to clients. Normally the DHCP server provides the client with at least this basic information: •IP Address,•Subnet Mask,•Default Gateway. Other information can be provided as well, such as Domain Name Service (DNS) server addresses and Windows Internet Name Service (WINS) server addresses. The system administrator configures the DHCP server with the options that are parsed out to the client.

Hyper Text Transfer Protocol HTTP takes care of the communication between a web server and a web browser. HTTP is used for sending requests from a web client (a browser) to a web server, returning web content (web pages) from the server back to the client. HTTPs run over an encrypted SSL session (HTTP over SSL (Secure Sockets Layer)). So, if the website begins with https:// instead of http://, it is a secure site. Client and server need to create a shared secret key by using a public / private key handshake. Typically, HTTP data is sent over TCP/IP port 80, whereas SSL HTTP data is sent over port 443.
FTP - FTP refers to a network protocol responsible for transferring files from one computer to another on the Internet. The FTP service is provided through a TCP network protocol. In order to establish an FTP connection the user needs to point his FTP client to an FTP server. The information needed includes an FTP host, FTP account credentials (username or password) and a FTP port. The default command port for FTP connections is port 21.

Internet Control Message Protocol takes care of error-handling in the network. It is chiefly used by networked computers' operating systems to send error messages—indicating, for instance, that a requested service is not available or that a host or router could not be reached

Simple Network Management Protocol. It is used mostly in network management systems to monitor network-attached devices for conditions that warrant administrative attention

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