I want to block 'orkut' in my network with websense, when i am trying with the same, 'gmail' also got blocked, how can i block 'orkut' with out affecting gamil by websense...
Yes its better to use the pattern matching as the earlier poster described, if you do nslookup of both the google webpage and orkut, you see one very interesting thing:
Addresses: 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206
Compare the two A records, both contain *.google.com. So thats why websense is thinking both to be the same, both are sub-domains of the same domain.
You could also maybe put www.google.com in a White List or something.
In Websense v6.3.2 (possibly earlier versions as well) you can block by URL Patterns. Simply place the word orkut in your policies to block and that should do it.
Worst case, you can use RegEX in your firewalls/routers and block it that way.