[HELP] Vbulletin 4.2.1 can't search keywords .com or "-"

[InvestDad.com]

Hello tbworld,
It is nice to see your quick reply.

Set search type here:
Admin CP -> vBulletin Options -> Search Type - There is only one option DB Search

Change Character length:
Admin CP -> vBulletin Options -> Message Searching Options -> Search Index Minimum Word Length and Search Index Maximum Word Length
Minimum Word Length set to 4 - Maximum Word Length set to 20
I want to search keywords like "google.com" or "yahoo.com" then in Words to be Included Despite Character Limit, what I should enter here? Because when I enter "google" or "yahoo" it returns results but with ".com or .net" then no result.

Can you please advise me more on this matter?
Thanks so much