Go Back   Computer Forums > General Computing > Networking | DNS
Click Here to Login
Join Computer forums Today


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-12-2009, 03:18 AM   #1
In Runtime
 
Join Date: Apr 2009
Posts: 129
Default packet routing

When 5 computers behind a NAT router browse the internet, how does the router know which computer to send the data that came back from the internet?

I just used a remote access program, logmein, and I'm wonder how it works without me configuring port forwarding in my router.
__________________

david90 is offline   Reply With Quote
Old 06-12-2009, 11:27 AM   #2
Fully Optimized
 
vampist's Avatar
 
Join Date: Oct 2008
Location: USA
Posts: 2,404
Default Re: packet routing

Well It's pretty simple.
You can think of it like a mail truck and ordering a catalog.
You send out the order for the catalog.
You put the order in your mail box, which gets to your mail truck guy.
Then he sends it through the mail to the specific address for the catalog.
The company with the catalog goes ok they want this.
Then sends back the catalog through the mail.
Sending it eventually to your mail guy.
Who then brings it to your house.

If you want to know more please Click Here
__________________

__________________
Everyone's Favorite Turd xD
ET: "Phone home!"
Geek: "ping 127.0.0.1"

"If that guy knew half the $h*t that I know, his fuzzy little head would explode. " - Matthew Farrell
vampist is offline   Reply With Quote
Old 06-12-2009, 02:03 PM   #3
In Runtime
 
Join Date: Apr 2009
Posts: 129
Default Re: packet routing

but if there are 5 houses, how does the mail man know which house to deliver the catalog to? I'm not talking about local LAN packets but packets from the internet. LAN packets have a destination and source address thus the router knows where to send the packets.

I'm talking about the internet packets. If I send a request to a server on the internet, the router strip my local ip and replaced it with the public IP from my ISP. When the request comes back, packet doesn't contain any information on which computer behind the router it is suppose to go to so how does the router know where to route it?
david90 is offline   Reply With Quote
Old 06-12-2009, 04:03 PM   #4
Fully Optimized
 
vampist's Avatar
 
Join Date: Oct 2008
Location: USA
Posts: 2,404
Default Re: packet routing

Quote:
Originally Posted by david90 View Post
but if there are 5 houses, how does the mail man know which house to deliver the catalog to? I'm not talking about local LAN packets but packets from the internet. LAN packets have a destination and source address thus the router knows where to send the packets.

I'm talking about the internet packets. If I send a request to a server on the internet, the router strip my local ip and replaced it with the public IP from my ISP. When the request comes back, packet doesn't contain any information on which computer behind the router it is suppose to go to so how does the router know where to route it?
It doesn't necessarily "strip" your local ip.

You see websites that are running "http" are on port 80. "https" is port 443, "ftp" is port 21.

Your web browser and your router will listen to these ports after sending out a request. If the server does not respond say.. The catalog doesn't come in the mail. You would me mad of course.. What the browser does is time out. You then get a 400 (bad request), 404(not found) 408(timed out) error.

So the sending packet from the server(website) may not know the LAN computer. But the router and computer your on are listening for the request. Once they hear the request from the location you requested it is then displayed.
__________________
Everyone's Favorite Turd xD
ET: "Phone home!"
Geek: "ping 127.0.0.1"

"If that guy knew half the $h*t that I know, his fuzzy little head would explode. " - Matthew Farrell
vampist is offline   Reply With Quote
Old 06-13-2009, 11:08 AM   #5
In Runtime
 
Join Date: Oct 2005
Posts: 140
Default Re: packet routing

for a more in depth explanation

http://technet.microsoft.com/en-us/l...22(WS.10).aspx
user12 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -5. The time now is 03:08 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.6.0