what is the difference between internal and external ip address?

Question

i am a little bit confuzed about that so please help

Answer 1

An internal ip address is visible and usable only on your home or office intranet. Example: you have cable internet, one modem, and 3 computers that you want to have access to the internet. You install a router on your network and it will assign (or you can) each computer on your network an internal ip address. They start out 192.168.xxx.xxx. This is like your router giving each computer a ticket or a pass to the Internet.

The router has the external ip address from you ISP. That's ip address that the world sees.

Answer 2

Internal/external simply describes the relative positions on a LAN/WAN. The external interface is for the WAN/primary LAN, and the internal interface is for the LAN that used the "internal" connection as a gateway. A good example would be a standard home router, the external IP is whatever public IP the ISP assigns, while the internal address is 192.168.1.1 (or any other NAT address). MAC address spoofing depends on the operating system. With WIndows, it is a minor registry modification, with UNIX, it is simply running ifconfig and specifying the adapter and new MAC address. MAC spoofing has very few uses. It can resolve duplicate MAC issues, although those a very rare, and it can be used to bypass MAC address restrictions put in place by ISPs, allowing you to use a router, or a different computer than the one you registered. All it does is change the hardware address of the network adapter. Nothing malicious or useful.

Answer 3

Basically, every computer on the Internet has an IP address, e.g. a unique identifier available to everyone (the "external", or public, address). Every computer is identified by the format 255.255.255.255.

Therefore, there are "theoretically" 255 x 255 x 255 x 255 = 4,228,250,625 computers/servers that can connect to the internet. (FYI, IP v6 is supposed to raise the limit of number of computer on the Internet. But don't expect it anytime soon...)

While this limit seems high, this limit can be reached quite fast because people (e.g. companies) have more than one address. Imagine Microsoft or the US army, they have tons of adresses!

So, one way of bypassing this is by creating a "private" (or internal) network withing a company, or even within your house! Most private networks have the format 192.168.xxx.xxx, or 10.0.xxx.xxx since these networks have been reserved and are therefore "invalid" on the public Internet.

If you buy an Internet gateway for your house (Linksys, Netgear, etc.), you'll get an "internal" IP address. However, your router will have an "external" IP address, visible to other computers on the Internet.

In practice, what this means, is that every computer in your "internal" network will have the same IP address "seen" from other computers on the Internet, because they'll be sharing a single external IP address.

This is therefore a very effective way of multiplying the available IP adresses on the Internet.

Answer 4

If you're referring to a wireless network, there are addresses that you own and the world sees you as. This is a unique IP that no one else shares. But the wireless pc's that are sharing that main connection have "internal" IP addresses that are probably only unique on your internal network.

Answer 5

Internal is on your LAN network. External is the other side of your router, an Internet routable address.