Connectivity to Internet and Exchange can be configured in several ways on a network.
1. Access to the internet can be configured using a Direct mode or via a WebRequest
Changing the internet ping strategy to an alternate may resolve the error "Internet not Available"
Strategy A - Direct
Strategy B - Web Proxy
Similarly
2. Access to Exchange can be configured Direct via http or via Proxy or via Exchange Service
Changing the internet ping strategy to an alternate may resolve the error "Exchange not Available"
Strategy A - Direct
Strategy B - Web Proxy
Strategy C - Exchange Service