[rudra]

how about using fail2ban. or may be you could use whitelist approach. ban all to the teamspeak port. only allow from ip ranges that match your user isp ranges. it will be helpful cause i am sure it will involve much less checking. fail2ban type auto ban service is good too. it sends offending traffic to just vanish. though if it is some kind of DDoS or even DoS that is taking up the capacity of the network, then your filter or whatever preventative measures you take will have to be further ahead in the chain of things. you cant deal with high volume DoS attacks right at the target.

trying it is a bit like trying to push start a car while you are totally in it.

i dont know anything about game server setups. so pardon my ignorance.