View Feed
Coffee Room
Discuss anything here - everything that you wish to discuss with fellow engineers.
12914 Members
Join this group to post and comment.
abhimanipal • Jan 13, 2007


can some one tell me tht when one ,makes a connection to the web through a dial up service wht is the sequence of steps tht the computer takes ???with steps i refer to opening of ports and all !!!!i hope my question is clear to everyone !!!!!!!!
pad • Jan 18, 2007
let us see in two parts.

1. Networking part.

2. Application part

1. Networking part
First a dialup connection is estabilished from your host to the ISP. (there will be a RAS server accepting client connections). Each connection is asigned on IP address, one DNS and one gateway. here a point to point (ppp) connection is formed. This connection is usualy on SLIP.

2. Application part
let us say is typed in Firefox.
Firefox opens a socket passing hostname / and port no 80 (this is default for http). again lower layer resolves this host name with DNS (localy cached info or from a fresh query) and opens the connection with the destination with port 80 and IP returned by DNS query.
OS sends all the packets to the default gateway (given by ISP in ppp connection phase). A three way handshake takes place and connection is complete(on TCP layer). now application data is passed i.e. complete URL which gets passed to the web-server (or application server) and server responds with the answer for /GET/ request.
this result is fed to FF and u see your darling forum

aashima • Jan 18, 2007
Too good information Pad. Really it was great to know. I hope the query is clear.

Share this content on your social channels -