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[incka]

Is class C the xxx in 543.454.xxx.565 ?

[chromate]

A class C IP is where the first octet is between 192 and 223. The network is made up of xxx.xxx.xxx and the host is the last octet.

I don't think it's necesarily important to have a different class c address in particular. What probably matters is that the sites are on different networks (indicated by the first 3 octets of a class C, the first 2 of a class B etc etc)