HTTP

• Hypertext Transfer Protocol is used to share and request information

HTTP Requests

HTTP Verbs

1. GET
   1. Retrieves data from the server
   2. Idempotent
   3. Includes sensitive information in the URI, which can be logged
2. PUT
   1. Updating an existing resource or create a new resource of it doesn't exist
   2. Idempotent
3. POST
   1. Creating a new resource
   2. Not idempotent (multiple identical requests results in different outcomes)
   3. Does not include form data in the request URI; instead, form data is encoded in a URL, and calls a function on the server to process the information
4. HEAD
   1. Retrieving metadata about a source without fetching the actual data
      1. HTML standard prevents HEAD requests from containing message body/form data
      2. Typically only used to extract header information or test HTML links
   2. Idempotent

HTTP Response Codes

1. 1xx - Informational
   1. The request was received, continuing process
2. 2xx - Successful
   1. The request was successfully received, understood, and accepted
3. 3xx - Redirection
   1. Further action needs to be taken in order to complete the request
4. 4xx - Client Error
   1. The rest contains bad syntax or could not be fulfilled
5. 5xx - Server Error
   1. The server failed to fulfill an apparently valid request

Metadata

OSI or TCP/IP Layer

CCNA Exam Topic

Contributors

Sources