Hi Mar8ix,
not sure it's still globally in use but there is the list of the differrent simulator IP ranges : http://wiki.secondlife.com/wiki/Simulator_IP_Addresses
see also :
http://community.secondlife.com/t5/English-Knowledge-Base/Using-Second-Life-with-a-firewall/ta-p/1304539
Hope that's help,
Fleur.