If you try to open general settings of a web application in sharepoint and get an error "Updates are currently disallowed on GET requests. To allow updates on a GET, set the 'AllowUnsafeUpdates' property on SPWeb.”

You can try this script from powershell.

$myweb = get-spwebapplication http://nameofproblemwebapp
$myweb.HttpThrottleSettings
$myweb.Update()