Home Security Security General Security Warning - Exposed WAN Link Identity by reverse lookup

If someone knows what is your IP address of WAN link, if someone knows what ISP you are currently using, if someone knows where your link is connected, isn't that scary ? Of course, that is definitely "NO GOOD".  Your traffic would be the easy target for hackers.

How they know all the information? It's quit simple. Most of ISP assigns /30 IP address block for connectivity between their edge device and CPE(Customer Premises Equipment) from big chunk of  reserved IP block such as /16, B class IP block. So easy to recognize WAN IP address by traceroute. I don't want to make a list of the IP blocks that ISP reserves for customer WAN link here. However, just googling the information, you will get it easily.

Another security warning on reverse-lookup data. Some of ISP update customer account#, interface and customer name on DNS reverse-lookup zone file.

Try reserve-lookup data on your WAN IP address, what information comes to you.

DOS prompt> nslookup x.x.x.x

You might surprise with the output.

If you are allocated IP block from your upstream provider, try reserve-lookup date for your IP block. It might expose your company name or IP assignment information.

Security hole is where you never expect!


Last Updated (Friday, 09 October 2009 21:57)

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