If you do work with load balances, checking that a URL is up (200 ok) is common, here is a simple use of powershell and wget to see if it is up. With proxy and with proxy.
wget 'http://dave.colv.in/' | % { "$($_.StatusCode) $($_.StatusDescription)" }
wget 'http://dave.colv.in/' -proxy 'http://you.proxy.here:8080' | % { "$($_.StatusCode) $($_.StatusDescription)" }
wget 'http://dave.colv.in/' | % { "$($_.StatusCode) $($_.StatusDescription)" }
wget 'http://dave.colv.in/' -proxy 'http://you.proxy.here:8080' | % { "$($_.StatusCode) $($_.StatusDescription)" }
