allowing access to php page by IP

Hello, I want to allow access to a php page but am not sure how I should verify the IP once I get it. I want to allow 10.8.4.* and 10.8.5.* to access a certain webpage and keep everyone else out. I have written code to figure out what someone's IP is, but am not sure about how I should verify whether the IP is in the range of 10.8.4.* or 10.8.5.*. Any suggestions? I was thinking of either using a regex (but I dunno regex so I'd have to learn it) to stip off the .* octect and then compare the rest of the IP and see if its either 10.8.4 or 10.8.5, or create a for loop and loop through 1-254 and cat it to the end of 10.8.4. and 10.8.5. and compare it to the IP they are coming from. Any suggestions on how I should do it? Here is the code I have to get the IP: if (getenv("HTTP_CLIENT_IP")) { $ip = getenv("HTTP_CLIENT_IP"); } elseif (getenv("HTTP_X_FORWARDED_FOR")) { $ip = getenv("HTTP_X_FORWARDED_FOR"); } elseif (getenv("REMOTE_ADDR")) { $ip = getenv("REMOTE_ADDR"); } else $ip = "UNKNOWN"; Thanks, Adam