LinuxQuestions.org
Welcome to the most active Linux Forum on the web.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices


Reply
  Search this Thread
Old 07-31-2007, 12:49 AM   #1
raklo
Member
 
Registered: Apr 2006
Posts: 143

Rep: Reputation: 15
TCP/IP protocol stack query ??????


hi all,
i m confusd bout certain fields of IP header cud u solve them

1)wot wd be the fate of packet if TTL=0 ??

2)wot wd be the fate of packet if TTL=1 ??

3)If my packet is not fragmented,then is there any
use of Identification field in the IP header???

4) If i wanna add my own custom byte into the ip header
,wotz the least laborious way to do it???

regards
 
Old 07-31-2007, 01:04 AM   #2
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,417

Rep: Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985
1) it'd be timed out as ttl expired

2) TTL is decremented to 0 as it moves to the next hop, then as 1).

3) no

4) edit the tcpip stack code on all affected systems i guess.
 
Old 07-31-2007, 01:13 AM   #3
raklo
Member
 
Registered: Apr 2006
Posts: 143

Original Poster
Rep: Reputation: 15
thanx a lot,for this upto the mark reply.
for the ans 2) that u gave.
does the TTL decrement at the sender level,or at the receipent level.i.e,is it
decremented and sent,or sent and then at the other side decremented????

for the ans 3) that u gave,
if my packet is not fragmented,if i fill identification field with random bits
then wud that make a difference???


for the ans 4) ,
do u think raw sockets will help me in anyway for my purpose???n also
at which layer r the sockets formed??

regards
 
Old 07-31-2007, 04:27 AM   #4
raklo
Member
 
Registered: Apr 2006
Posts: 143

Original Poster
Rep: Reputation: 15
also cd anyone tell me at which layer is TTL checked????
 
Old 07-31-2007, 07:09 AM   #5
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,417

Rep: Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985
well for 2 i assume the ttl is decremented as it is sent on to the next hop, as if it were addressed for itself it wouldn't decrement.

for 3 and 4 i have no idea... read the tcp/ip standards and ttl is an IP attribute, so would be checked at the layer equivalent to IP. i'm sure you can find which one that is yourself.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
TCP cannections in TCP stack hegdeshashi Linux - Networking 1 01-04-2006 07:24 PM
Network protocol stack corruption. Has it ever happened? tomdkat Linux - Networking 1 11-27-2005 09:42 AM
getting new tcp/ip stack on linux cdp Linux - Networking 7 06-29-2005 12:50 PM
Making changes to Linux network protocol stack kayko2000 Linux - Networking 0 10-13-2003 05:27 PM
TCP/IP Stack on Linux? Rossak Linux - Networking 2 07-27-2003 06:20 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 05:53 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration