You could see if you have iptables installed (the defacto firewall in Linux kernels 2.4 and up (or is it 2.6??)).
if it cant find iptables try
find / -name "iptables"
To try and find the binary for it.
if it is installed you could create rules for incoming on that port. Google for iptables resources, it's not a 2 second job.