- Verify that the protocol of the request is serviceable (for example ICMP, UDP, may be blocked by the proxy server).
- Ask user to authenticate that the proxy server does not already recognize him/her the user as being logged in.
- Verify that the source address of the request is on the list of allowed workstations.
- Verify that the requested network object is not blocked by an Internet content filter. (Most Internet content filter vendors provide lists of sites organized by category that administrators can decide to block or allow.)
- Check the proxy server’s local disk to see whether the requested object exists in cache. (If the object is in cache, the proxy server will send it directly to the requestor without having to access it from the Internet.)