Redirect user on specified route I know we can easily redirect a path to another path with Redirect module, but what I want to do is more complicated,  my condition is when the user has a specified IP and the route is matched with to a specified path redirect it.

Pseudo code what I'm looking for is 

if $path='xxxxx' and $user_ip = 'yyy.yyy.yyy.yyy' redirect to 'zzzzz'


how I can implement this, what I need is where is the best place to implement this?
You can alter the routes (conditionally based on IP) by creating an event subscriber or by using a RouteSubscriber.  You should also look at altering existing routes.