I think utilizing a firewall at the router level would be one way to deal with the problem, but it will take time to determine and implement the appropriate rul

I think utilizing a firewall at the router level would be one way to deal with the problem, but it will take time to determine and implement the appropriate rules (a popular choice on HN is the EdgeRouter Lite3 from Ubiquiti). There may be Linux equivalents of the tools you use, but it would be difficult to say without you naming these tools specifically.