Post #508083

2026-03-03 17:01 UTC

The routing and firewalling is a bit different in terms of why certain CIDR masks are used. For the router, the /24 prefix is usually defined for itself on the LAN interface to denote the address space it may send route information to, and what addresses are controlled by the device. Almost certainly, (unless using a lower CIDR range and actually handing out /24 blocks to subsequent routers), you are granting /32 IPv4 addresses to your device from your router. For your system firewall, 192.168.1.135/24 is identical to 192.168.1.0/24 as they are the same address space. You’re simply allowing from a subnet of hosts to accept from. Given the /24 mask is 255.255.255.0, it does not matter what the last number of the IPv4 address is, but the lowest possible number to match the mask is standard form. Without knowing what rule(s) specifically are being applied, I couldn’t tell you if your firewall rules are something that would affect hostname resolution of other hosts from your system or not.

Replies (2)

@emotional_soup_88__dup_21417@programming.dev 2026-03-03 17:20

Just when you think you know something about networking, it turns out you don’t know sh*t. XD Thank you for your exquisite explanation and for immediately realizing what I had been misunderstanding!

Open ##508126
@emotional_soup_88__dup_21417@programming.dev 2026-03-03 18:10

If I may ask a follow up question, just out of curiosity, I did an ip a on my phone that is connected to the same router as the system whose firewal I was referring to in my original post and it gave me: inet 192.168.1.214/24 brd 192.168.1.255 scope global wlan0 Which to my untrained eye indicates that my phones WiFi interface has been alotted the .214 address in the /24 space/subnet. But if I understand you correctly, this has to do with the above being routing related - how my phone reaches WAN -, while my original post was about firewalling. And when it comes to firewalling, you specify a host with a mask of /32?

Open ##508167