Thailand Internet firewall?

Hi, Is anyone aware whether or not Thailand has a centralized firewall on Internet access? We've had reports from several folks in Thailand that they are unable to get to some IP addresses in our network (this problem is reproducible on the traceroute.org Thailand sites as well). It seems to only be from Thailand, and only certain IPs on our network Does anyone know how to contact whoever is responsible for this firewall system to find out at the very least why this block is in place? thanks, -Drew