So when someone is abusing a person with hotmail / yahoo mail etc I can see his IP address so how to i track his ISP with his IP address so i can report that to his ISP anyone know how

You can always use the command tracert (traceroute on Unix machines), which will resolve an IP address into a hostname (as well as show a router path to the address), which can then be easily resolved via a whois query (use internic.net or an equivalent) to determine the owner of the address. Generally, this yields little concrete results though. IP addresses are sold in blocks, which are then resold and resold until they are provided in large blocks to businesses or individual addresses to the majority of users. Most users access the Internet through one shared address and firewalls commonly block tracing attempts beyond backbone networks. Also dynamic IP allocation is common. Let's take one address and find the ISP and owner. tracert 65.105.158.150 It resolves to 65.105.158.150.ptr.us.xo.net None of the hops return, so we can assume the address is not running a public service - i.e. it is behind a strict firewall and/or may be a client machine (which could even be offline). Now lets run a whois query at internic.net (arin.net has the same service). XO corporation owns the IP block. The whois also gives us several contact options for abuse, administration, and operations. From xo.net we know XO is an ISP. The address could be from a corporate or home user. Regardless, we have an ISP.