IP Address Issues

[Stepen]

When I search IP address of a websites some online tools are showing like this:

Domain Url IP Address Class C Duplicate Subnet Duplicate

Simultaneously its showing niche results.

http:domainname.com 174.102.245.111 N N

I want to know what's the meaning of "Class C Duplicate" and "Subnet Duplicate"

Any valuable opinion,need here.

[Manov]

Try the below link,
http://publib.boulder.ibm.com/infocenter/dsichelp/ds6000ic/index.jsp?topic=%2Fcom.ibm.storage.smric.help.doc% 2Ff2d_trblrslvipissues_1wwmn0.html