DNS Tools

Verify your site's DNS

intoDNS - Test DNS records

Recursive DNS Tool

TraceRoute

Domain Whois Lookups

Who Is Domain or IP Lookup

Networksolutions Whois

Ripe Whois

ARIN Whois

APNIC Whois

Your IP Lookup

I Can HaZip - IPV4

I Can HaZip - IPV6

IP Calculators

MxToolbox Subnet Calculator 

CIDR XYZ 

IpAddressGuide