Same IP address on my network?

me and my brother have 4 computers on my home lan, and connect to the internet through a linksys router. whenever we post on a message board, or chat in IRC it says our IPs are identicle :confused: anyone know why this is?

That is because you truly only have one IP address.

The router uses NAT to separate your lan from the internet. It cuts down on the amount of ip addresses that you need to have. This is good for a couple of reasons... it makes your LAN private and it also cuts down on the number of ip addresses that are being used. It will also hide your identity on the internet... but only to your network, not to your machine as if you had a public ip address.

So... your LAN ip addresses are different, but your WAN ip address is the same.

The only way to change that would to either get a secone ip address from your ISP which will cost more $$... or you can use a proxy. Proxies will hid your tru identity but it is also possible for anyone running the Proxy to see what you are doing and possibly grab usernames and passwords if you enter them.

It is OK for you both to have the same IP.

Here is some more info on NAT. Its short and pretty easy to understand.

RFC1631 will give you the nitty gritty about it.

THANK YOU! :D
i have been kicked from many IRC channels because the admins think me and my brother are the same person

also, the same will happen with some games if you try to play online and on your lan at the same time. game developers don't take that into account ... I use to play stracraft like made and could only play with my roomate or online but not all toghether ....

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Originally posted here by Simo
THANK YOU! :D
i have been kicked from many IRC channels because the admins think me and my brother are the same person

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Yeah, I've had this happen too. Unfortunately, not all IRC channel ops are quite as computer/network litterate as AOers; most of them wont even try listening/understanding if you try explaining to them what NAT is...

You'd think they'd have gotten a clue yet, as home gateway/routers (using NAT) are getting so common.

Ammo

look at is also from an enterprise point of view, for example a company with 2 OC3's to the internet serving 13,000+ users all sharring a small pool of NAT'd IP address'. This can pose a big problem with apps such as VPN, Games, etc... If you are interested in how to solve these issues on a grand scale do some searches on Content services switches. These are upper layer protocol routers that route based on the content needed (Virtual Ports) and can run NAT/DNS/Web services/Cacheing etc... This is the future of networking my friends.

Ulter C. Sceadu: I agree with you on most of what you've said. Though... I have thought that IPv6 will solve most of these IP problems... Granted... IPv6 won't solve everything that Content services switches would help solve...

you could try and enable the dhcp server in you router if it has one then when it allocates
the addreses will be differant

Go to google and do a search on a free proxy utility... like phishphreek80 said that should fix the problem.

just wait for IPv6 then there'll be enough IP adresses to assign one to evry person and their pets ;)