{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

1 developed browserserver persistent connec8ons

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: org. Snapshot on 27.02.12. Does not represent current deployment. 118 DNS Protocol •  Query and response messages –  Built on UDP messages, port 53 –  ARQ for reliability; server is stateless! –  Messages linked by a 16- bit ID field Client Query Server ID=0x1234 Time ID=0x1234 Response 119 13 11/26/13 DNS Protocol (2) •  Service reliability via replicas –  Run mul8ple nameservers for domain –  Return the list; clients use one answer –  Helps distribute load too NS for uw.edu? Use A, B or C A B C 120 DNS Protocol (3) •  Security is a major issue –  Compromise redirects to wrong site! –  Not part of ini8al protocols .. •  DNSSEC (DNS Security Extensions) –  Long under development, now par8ally deployed. We’ll look at it later Um, security?? 121 14 11/26/13 Introduc8on to Computer Networks HTTP, the HyperText Transfer Protocol (§7.3.1- 7.3.4) Computer Science & Engineering Topic •  HTTP, (HyperText Transfer Protocol) –  Basis for fetching Web pages request Network 123 15 11/26/13 Web Context Page as a set of related HTTP transac8ons HTTP request HTTP response 124 Web Protocol Context •  HTTP is a request/response protocol for fetching Web resources –  Runs on TCP, typically port 80 –  Part of browser/server app browser HTTP TCP IP 802.11 request response server HTTP TCP IP 802.11 125 16 11/26/13 Fetching a Web page with HTTP •  Start with the page URL: hfp://en.wikipedia.org/wiki/Vegemite Protocol Server Page on server •  Steps: –  Resolve the server to IP address (DNS) –  Set up...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern