|Might want to google dhcp [dynamic host configuation protocol] for why your address changes.|
You can either do ip address reservation / mac address filtering in the router to assign a static ip via dhcp to the ps3
set the ps3 to a static ip address and remove that ip address from the routers dhcp scope.
for example if using 18.104.22.168 for router you could set 192.168.1.254 as the ip for the ps3 and your dhcp scope would be 192.168.1.2 to 253
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