Router's QoS settings: are IP address subnet masks necessary?

Question

Setting up my router's QoS settings, I can prioritize traffic according to a source IP address. However, alongside this, I'm also given the option of inputting that address' subnet mask. Is it necessary? I want to prioritize traffic exclusively from that address, not from a range of addresses. Should I leave it blank? What difference should it make? What value should I input? Could it somehow affect NAT settings? (The source IP address is private; it's 192.168.1.2 and its network subnet mask is 255.255.255.0.)

Answer 1

If you want it only for that specific address then you use the /32 or 255.255.255.255 subnet mask otherwise generally leaving it blank means the same thing. If you wanted the entire 192.168.1.x network to be considered then you would use the /24 or 255.255.255.0 netmask.