You can control client access to Content Gateway from the ip_allow.config file by specifying ranges of IP addresses that are allowed to use the proxy. If Content Gateway receives a request from an IP address not listed in a range specified in the file, it discards the request. See ip_allow.config.

If you do not know the ranges of client IP addresses allowed to access Content Gateway, you can add rules to the ipnat.conf file so that only requests that have been redirected by your Layer 4 switch or WCCP router reach the proxy port. To make a transparent-only Content Gateway server, add rules in the ipnat.conf file before the normal redirect service rule to redirect explicit proxy traffic to a port on which no service is listening. For example, if you want Content Gateway to ignore explicit HTTP requests, add rules above the normal HTTP redirect rule in the ipnat.conf file as shown below (where ipaddress is the IP address of your Content Gateway system and port_number is a port number on which no service is listening):

If your Content Gateway system has multiple network interfaces or if you configure the Content Gateway operating system to use virtual IP addresses, you can give Content Gateway two IP addresses. One address must be the real address that the proxy uses to communicate with origin servers and the other a private IP address (for example 10.0.0.1) for WCCP or switch redirection. After you configure the IP addresses, you must add the following variables to the end of the records.config file. Replace private_ipaddress with the private IP address used for WCCP or switch redirection and real_ipaddress with the IP address the proxy uses to communicate with origin servers.