Gamespy flooding of TPU on UDP port 23000 seems to be under control, at least for now. I can see flood traffic arriving at the router sporadically, but it's all being dropped. Research shows that TPU is not the target of these attacks, but rather was being used as a reflector in a DRDoS (Distributed, Reflected Denial of Service) attack against one or more other servers.

Below are the IPs I am continuing to block. If you are aware of some reason why any of these should be unblocked, let me know.

78.145.117.49
82.21.203.53
85.234.149.219
94.76.216.44
109.70.148.51
220.25.130.98
89.176.28.198
24.110.31.66
76.111.53.176
184.106.242.223
66.8.194.174
81.19.212.130
96.31.86.166
69.14.213.132
72.10.172.39
67.215.65.132
184.4.130.120
74.72.216.160
108.65.237.65
208.167.232.92
64.120.251.131
209.246.142.73
24.184.255.80
69.175.48.194
64.79.109.136