Multiple TCP connections

ranban282 · 08-12-2009, 08:36 AM

Hello,
I'm curious to know what happens when 2 connections are opened from host A to host B (Let's say that B's a web server, and A has multiple browsers konqueror and firefox open and hitting the same site). How is it ensured that the content on firefox is the one that was meant for firefox, and not the content intended for konqueror.

I suppose that an analogous situation in UDP would be application x and application y on box A try to retrieve a message from box B on port p. How is it ensured that A doesn't get B's message?

Thanks in advance

bsdunix · 08-12-2009, 09:16 AM

The Session Layer provides the mechanism for opening, closing and managing a session between end-user application processes
http://en.wikipedia.org/wiki/Session_Layer

Each TCP/IP network connection from client A to server B will have it's own network port connection.

http://www.ipprimer.com/tcpudp.cfm

Some other helpful info using command netstat with example:

If we needed to know exactly which application owned a particular network connection, we would use the -p | --program switch which gives us the PID and process name of the owner process. If we want to see the unix user and the PID and process we'll add the -e | --extend switch.

Code:

# netstat -p -e --inet --numeric-hosts
Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode      PID/Program name   
tcp        0      0 192.168.100.254:ssh     192.168.100.17:49796    ESTABLISHED root       25453      6326/sshd
tcp        0    240 192.168.99.254:ssh      192.168.99.35:42948     ESTABLISHED root       171748     31535/sshd

http://linux-ip.net/html/tools-netstat.html

ranban282 · 08-13-2009, 04:04 PM

Thanks for your response - I understood it when I used wireshark.