Its a class C checker is a IP checker - http://www.webrankinfo.com/english/tools/class-c-checker.php You can check your site IP - & In which directory you are submitting your site link, it will view that website IP - don't submit in same IP. For more search in google ok
Its an IP address in a certain IP block; If you consider that the following is a standard (internal) IP address: 10.24.32.98 This can be broken down as follows; a.b.c.d Therefore, a class C IP, in this example, is anything in this range; 10.24.32.0 - 10.24.32.255 The whole "class C" backlink thing is a tad rediculous too; sure, you should not get all of your backlinks from a single IP address, but bear in mind that HTTP1.1 allows many thousands of websites to be hosted on the same server/cluster, you will not be penalised for having backlinks from the same "address".