Web Redirection for Content Scanning

This specification generally relates to using redirect messages to implement content scanning. One example method includes receiving from a client a first request for a network resource, the first request including an original location of the network resource; determining that a response to the first request is to be analyzed; sending a redirect response to the client including a modified location for the network resource different than the original location; receiving a second request for the network resource from the client, the second request including the modified location; in response to receiving the second request for the network resource from the client: retrieving the network resource from the original location; determining that the retrieved network resource is suitable to send to the client; and in response to determining that the retrieved network resource is suitable, sending the retrieved network resource to the client.