easiest way to only permit certain hostnames from connecting to script?

[Fog Juice]

Hello, I only want servers with the hostname agni.lindenlab.com connecting to my script. The problem is, some of them have sim2342 in front so it could be sim2423.agni.lindenlab.com connecting or it could be sim6345.agni.lindenlab.com connecting.

 

I'm really crappy at using preg_match() for these sort of things, can someone build me a preg_match that only matches agni.lindenlab.com with wtv else is in front but nothing past agni.lindenlab.com? I.e. I dont want someone mimicking agni.lindenlab.com with something like agni.lindenlab.com.myrealdomainname.net.

 

 

Thanks so much!

[RussellReal]

$pattern = '/agni.lindenlab.com$/i';