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Difference Between WAN & LAN IP Address

TechBoi-215

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Aug 20, 2014
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Hello there techies


At my job, I work with routers and gateways. I know that WAN is the Wide Area Network (basically LAN's that are connected to other LAN's) and the LAN is the Local Area Network. Now something that I came across is that WAN and LAN have different IP addresses. I would like to know the following


1. Why are there two different IP addresses for both of these?

2. Are they both private IP addresses?

3. If you try to port forward into a LAN that is on a WAN, would you need just the LAN IP or both the WAN & LAN IP?

Bonus Question: Is it possible to port forward an IP address to another port the is on a router? E.G I have 10.xxx.xxx.xx.xxx on port 81 and 101.xxx.xxx.xxx.xx on port 80 but I want both these IP's to point to port 80


PS: I did try to find other threads on the first three questions, but to no avail, I could not =(
 
Solution
The device you are talking about is really only used to connect to the internet so in almost all cases wan means internet. The internet address are almost always public.

Now when you talk a enterprise installation there really is no common answer since it can be designed anyway you like. In most cases there is a interface that connects to a remote location or more and that can be called WAN but it can also be called MAN depending on the company. This device is a actual router and you can pretty much device interface how every you like. It really doesn't matter it is just a name to represent how far away something is. The IP used can be anything the company wants. Unless the company is very large they do not have public IP blocks to use internally. Pretty much the only companies that do that got their IP many years ago when it was easy to get huge blocks. The vast majority of companies that started putting networks say in the last 10 yr use private for everything since they could not get public to use on a internal network.
 


think of LAN and WAN as 2 sides of a gateway device. routers, modems, firewalls, for example are gateway devices. the WAN side faces the outside, the cloud, the internet. The LAN side faces the local area network.

1. they have different IP address because they have different functions.
2. they can be private or public, usually WAN is public and LAN is private
3. with most consumer grade devices you don't have to specify the WAN (public) IP. you just need port number and internal (private) IP address.
bonus answer: you can forward ports to only one internal IP address. forwarding port 80 to 2 internal IPs is not possible.

 


I see, the only reason I ask is because I know NAT is basically the converter for private IP's to go out onto a network. Would the WAN IP address that converted address?

I had a customer saying it was possible with the bonus question I asked, I know I'm not crazy XD
 


lets make sure we are on the same page. you have 1 public IP and 2 devices on the internal network, and you want to forward port 80 to both internal devices?
 


In layman's terms. I have device A with an IP of xx wanting to go through port 80 and device B with an IP of yyy through port 81. After this I would like the latter to also go through port 81

A ----> portforward --------> 80
B -----> portfoward --------> 81 and then --------> 80
 


how many public IPs do you have?
are devices A and B web servers?
 


The IP's weren't given but they were both some kind of servers
 


this is most likely about web servers since we are dealing with port 80. read about web server clustering and network load balancing. with the above techniques you can open port 80 to multiple devices.

 
Solution


Ah I see, thank you. I was quite busy this weekend so I didn't get a chance to respond. I appreciate your (and everyone elses) input