# LAN prob



## champ_rock (Dec 1, 2005)

i want to ask you a question...... 

what happens when in a lan 2 computers have same ip addresss and the same mac address............(it may sound impossible but it is possible)

i mean will one of the computer hang or will shutdown automatically?????


----------



## choudang (Dec 1, 2005)

the mac add can't be same... cuz its on the lan card... if i'm wrong plz correct me. 

you can not assign same ip add in a same network... one of the machine will start normally and other one will display IP crashing message.

yes.. you can assign same IP, but it should be diff network.


----------



## vijay_7287 (Dec 1, 2005)

the mac address cant be same !!!!

 if the ip's are same (which is also not possible since tht is ISP dependent)
 maybe there some kinda streamlining of data 

a weird ans for weird question !!!!


----------



## champ_rock (Dec 1, 2005)

macv ids can be changed ..........


----------



## __Virus__ (Dec 2, 2005)

champ_rock said:
			
		

> macv ids can be changed ..........



explain


----------



## bshrestha2 (Dec 2, 2005)

mac address is 32 bit long address in which 16 bit address is given by the cisco company and other bit is given by the manufacture so it is impossible .... to be the same....


----------



## champ_rock (Dec 2, 2005)

the mods would ban me up guys if i explained it sorry.............. but i want to know the after effects///////


----------



## rachitar (Dec 2, 2005)

To change the MAC Address Go To
My Computers->Properties->Hardware->DeviceManager->NetworkAdapters
Right Click on your LAN card.Then Go To
Properties->Advanced->LocallyAdministeredAddress
Check the option of your value and enter a 12 digit Hex Code 
Sometimes some companies have some rule about the starting letters of the address so the best option is to change the last few digits of your actual MAC address

You can manually configure 2 PC's to have the same IP even without making the 2 MAC Addresses same,but both wont function together at the same time.While 1 is on the network,you will get an error message when the 2nd comp with the same IP tries to connect


----------



## champ_rock (Dec 2, 2005)

this has very bad implications rachitar please edit ur post and remove that procedure................(it is illegal to change the unique id)


----------



## rachitar (Dec 2, 2005)

champ_rock said:
			
		

> this has very bad implications rachitar please edit ur post and remove that procedure................(it is illegal to change the unique id)



LOOK LOOK LOOK WHO IS TALKING!!!!!!
*www.thinkdigit.com/forum/viewtopic.php?t=31728&highlight=



			
				champ_rock said:
			
		

> its like this i ant to use my friends sify account as he has 256 kbps night unlimited... but the sify people use some kind of MAC and IP binding........ so i will change mine ti his and use his account.........



Looks like you just got OWNED


----------



## ashnik (Dec 2, 2005)

@champ_rock
BHOOTKAAL KABHIE PICHHA NAHI CHHODATAA !


----------



## champ_rock (Dec 3, 2005)

oops sorry u found out that........... but i realised it has more serious implications after i got a call from the sify people that they had detected my comp to be using someones else's account by illegally spoofing their mac id............

i asked this question in this post because i thought that maybe u could somehow know that 2 comp were running with a same mac id.........


----------



## maVen (Dec 3, 2005)

lol...hve been changn mac my comp ka mac adress since ages n using it to get acess to other users account as my internet provider give acess based on mac address..
My provider: PACENET

normally u cannot use another users login on ur pc, until u change ur mac address to tht of the other users address...

givin to comps same IP gives an error of conflictin IP nd both the computers cannot communicate with each other...

But would really like to knw wht happens whn both of thm have the same mac addr...

i dun feel it would hang or something like tht...


----------



## champ_rock (Dec 4, 2005)

hey mate doing the same thing here.............. sometimes........... but sify people figured it out somehow .......... that is why i have asked this question...... how the helll could they figure out......... same mac id same ip then what .........


----------



## siriusb (Dec 4, 2005)

Having the same mac id on more tahn one computer will confuse any bridge or switch that is in the subnet. Sify probably found out by this, or maybe they found two ppl logging in at the same time; I don't know about sify networks.
But you will have unncessary packets (from the correspondents of the other machine) that will go till your session layer. After this, the tcp port number should also match for your computer to recieve the packet and pass it on to the upper layers. It will be interesting to observe it in practise though. My bet is that, tyour computer will send "server not available" message if the port number don't match. If the port is also the same, then either the listenening app will crash or will ask the sending socket an error because the ack number don't match.
Anybody has two computers that can try this?


----------



## champ_rock (Dec 5, 2005)

yeah any volunteers to try that uot.......... there are many people here with alan


----------

