India Broadband Forum

Brightstar

I have seen a number posts on the forum as well as a document posted as Wireless Security Primer II, wherein users are encouraged to change the default IP of the router from 192.168.1.1 etc to any random number in the form xxx.xxx.xxx.xxx (as long as xxx is between 0 and 255). In fact the exact wording is

"Change your wireless router's IP address to something unguessable. And this is the main trick. A potential hacker knows that IP address of wireless router is likely to be 192.168.1.1 or 192.168.2.1 or 192.168.0.1, etc. A few tries and the hacker gets the router's login page. The username is almost always 'admin' and if the password is not strong - wham! the hacker is in and can see all your setup, WPA keys, etc.

Once the WPA key is known the hacker does not need to login again on your wireless router because it is unlikely that we will change WPA key again and again. The hacker has the WPA key and that is all is needed.

So the key is change your router's IP address to something unguessable such as 129.241.167.91 - well anything really - all those four digits could be any number from 0 to 255."

I have also learnt that Private IP addresses must start with 10.xxx.xxx.xxx, or 192.168.xxx.xxx, or 172.16.xxx.xxx to172.31.xxx.xxx
In my understanding any IP series other than these would be a Public IP ( and may be someone is already using that number) and we have to specifically get the IP allotted from ISP. Most ISPs also charge for public IP addresses.

Now the question is if many users start following the advice and change router IP randomly would it not lead to IP conflicts and anarchy? ....

Would someone please elucidate so that newbies like me are not confused

Admin

No it wont cause any issue as whatever you are doing is inside your local area network. Even if the whole world started using the same ip inside their local area network there would still not be an issue as all the networks will be working independen of each other.

The ip we assign as mentioned in that premir which was kindly prepared by our senior member Just4kix is not your internet connections ip address its just that you are assigning an ip to your computer so that your router recognises that computer with that particular ip but your WWW ip would still be assigned by your isp.

Brightstar

Dear admin,
Thanks a ton. Point understood. But then why the convention/practice of normally having private IP's as I had mentioned previously?

just4kix

Hello Brightstar,

You must first understand the difference between a public IP and a private IP. Public IP is seen in the outside world whereas private IP is what you see inside your own network. The public and private IPs never clash even if they are the same.

The IP addresses that are available are in the range 1~255.1~255.1~255.1~255. This means that the maximum number of computers possible over the internet (with real IP) are 255*255*255*255, i.e., 4,228,250,625 - roughly over 4 billion. And even though this is a huge number it will soon run out. For example, a big organization such as JP Morgan Chase or IBM or Bank of America will itself have tens of thousands of machines.

But by having a private network within one public IP address, it is "theoratically" possible to have those 4b + computers within a single public IP (of course this is not practically possible). This is where network address translation (NAT) comes in. NAT is a service within the router that translates the private IP address to a public IP address.

Hope this clarifies some of the doubts. I will be most happy to explain further.

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just4kix

That assumption is not correct - it is just a convention. You can have any IP address for your router. In fact, a BSNL customer can have the router's private IP in the range 59.xxx.xxx.xxx or 117.xxx.xxx.xxx (which are their public IP addresses).

Public and Private IP will never clash and router will correctly handle the same.

Brightstar

Many thanks to just4kix for the patience to explain the fundas to an illiterate but eager to understand user. I am obliged.
Thanks a ton.