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Can't open website with its IP address

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bugsbunnyboss

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I did a tracert to www.cisco.com and found its IP to be 92.122.0.170. I tried finding the IP of www.cisco.com through online IP finder and it gave me the IP as 96.17.128.170. The difference might be because these two are accessing two different servers of www.cisco.com.

Now my question is when I tried to paste the IP address in my browser's URL, it gives me "Invalid URL" error. Can someone please explain me why this is happening?

Thanks in advance.
 

throwaway18

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The Cisco website use the Akami content distribution network. You can look up those ip addresses in whois and see they belong to Akami.
Akami have servers all over the world, you are directed to the nearest one.

The reason that putting the ip address into your browser does not work is because the server hosts many different websites, it does not know which one you want.
Many years ago version 1.0 of the http protocol required each domain name to be on a different ip address.
Version 1.1 of http requires that the browser send a header giving the domain name, it allows many websites to be served from one ip address.
There is a shortage of ip address because in the 1990's some organizations got huge blocks and won't give them back.
It is no longer practical to have a different ip address for each website.
 

bugsbunnyboss

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Wow! This information is amazing. I was thinking we subnetted because of the lack of ip addresses, but had no idea that ip address was shared. BTW 92.122.0.170 resolved to akamaitechnologies.

So the fundamental concept of ip being unique has changed now?

One more question. If I'm pinging that ip, where am I getting the reply from - akamaitechnologies or from any other website inside akamaitechnologies?
 

Dan Mills

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Not at all, an IP address refers to a specific machine, but the mapping from a domain name to an IP address is many to one.

One server can serve foo.com, bar.org and baz.co.uk from the same IP address, just as it has always been possible to point an arbitary number of domain names at one server.

The key thing HTTP1.1 introduceed was the inclusion of the domain name in the HTTP request so as to allow the server to identify which site was being referred to (asking for index.html is not real useful in these conditions, asking for foo.com/index.html allows the server to deliver the correct site).
Prior to this you used to see things like foo.com:80 bar.org:81, baz.co.uk:82 as folk solved the problem by running multiple servers on different ports.

subnets do nothing to aleviate the shortage of V4 address space, that is what NAT is for, and there is **Plenty** of V6 space available.

73 Dan.
 

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bugsbunnyboss

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I read about NAT, and just wanted to check if my understanding is correct. I have 10 devices connected to my TP-Link TL-WR1043ND router. I have one dynamically assigned IP by my ISP. Is the router performing NAT overload to suffice for the 10 devices to be simultaneously connected?

Is there any way to see the NAT table in my router? I checked in the router interface and did not find any NAT table in it.

Finally, correct me if I'm wrong. If I configure a static NAT to one device, the other 9 devices loose internet connectivity and have only local connectivity?
 

Dan Mills

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No idea about the TPLink product, but 10:1 NAT on sane hardware is seldom going to be a problem unless something needs a huge number of open ports simultaniously (Not likely to happen in a consumer situation).

I don't really know quite what you mean by a 'static nat' usually what you do is to define port forwarding from one specific port on the external interface to a specific machine:port pair on your internal network, so for example I could have the NAT box forward port 22 to my SSH host without interfering with any outgoing connections from any of the machines inside the NATed network.

73 Dan.
 

bugsbunnyboss

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I don't really know quite what you mean by a 'static nat' usually what you do is to define port forwarding from one specific port on the external interface to a specific machine:port pair on your internal network, so for example I could have the NAT box forward port 22 to my SSH host without interfering with any outgoing connections from any of the machines inside the NATed network.
73 Dan.

As you mentioned, you are using the port address translation.

By static NAT, I mean mapping the internal IP to an external one (local IP to an ISP IP). I'm not sure if it is possible in TP-link though.
 

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