what is the requirement interms of connection speed and processor when expecting 30,000 clients mysql/php?

Answer 1

Depends on several factors:

1. Do you mean 30,000 visitors to your site on a daily basis or monthly basis..?
2. Does your site do a lot of processing?
3. What is your average home page load time etc..

However, I'd recommend a Dual Xeon processor with atleast 1 Gig RAM for even 30,000 visitors per month and site optimization done to reduce load on server.