Minimize game server delay with iptables

I have a debian 7 server hosted by Google Cloud running a game server and a rails server. The rails server run on port 80 and the game server on port 8000. I want to apply a network rule that allow the game server packets to have a higher priority in order to minimize latency. For now, I found that iptables could help me with this : iptables -A PREROUTING -t mangle -p tcp --dport 8000:8010 -j TOS --set-tos Minimize-Delay But when I check if my rule has been added : iptables -L -vt nat Chain PREROUTING (policy ACCEPT 877 packets, 100K bytes) pkts bytes target prot opt in out source destination Chain INPUT (policy ACCEPT 877 packets, 100K bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 329 packets, 20395 bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 329 packets, 20395 bytes) pkts bytes target prot opt in out source destination I'm not seeing my rule. What I'm doing wrong ? And also, is this the right way to do what I want ?