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krishna3010
Beginner

ipv6 and whatismyip when nat is on

how what is my ip works when nat is on. assuming all the isp's do nat, when i open whatismyip.com how can it say my exact ip on the pc. If nat is on my inside ip should not be know to the outside world as of rules. how is whatismyip.com website knowing my inside ip.

Coming to second question , in ipv6 why does the pc adds FFFE only as the padded bits in the host portion

someone help plz

regards

1 REPLY 1
Peter Paluch
Hall of Fame Cisco Employee

Hello,

The whatismyip.com will not show you your private IP address if you are behind NAT. On the contrary, the site will show you what is your public IP by simply looking at the source IP address of your request. After all, it would not make much sense telling you what is your private IP as you can always find it out directly on your PC. It is the public address after NAT that is often not known to ISP customers as it may change every now and then, and the whatismyip.com shows you what is your current public IP.

The FF:FE word added into the MAC address is used to inflate the 48-bit MAC into a 64-bit EUI address. The FF:FE word is specifically reserved to designate that a particular EUI-64 was created from a 48-bit MAC.

Best regards,

Peter