Network weirdness with supernetted class C in prvate space.


New member
Apr 11, 2023
I have a weirdness on the Steam Deck networking side I cannot explain. I am well versed in IP (and ICMP/TCP/UDP), networking (all OSI layers) and OSs (Windows, MacOS and misc Linuxes), but this one has me stumped...

My network is a subnet of the Class A, but relativey speaking a supernetted Class C inside it.
For example (actual IPs are different, but this is adequate for demonstrating the issue)

Def GW: (/23)
Steam Deck: (/23)

The Steam Deck can ping the whole subnet range, but can ony access over TCP the /24 subnet it's IP is in, so:
Ping works, ssh doesn't nor does
Ping works, as do ssh and
And (to add on to the confusion):
Ping works, as do ssh and (DNS lookups work as well!)

All other devices with IPs in the range work fine and communicate with all other devices, wether they have a 10.10.164.x or 10.10.165.x address.

There are no firewall internally, only on the perimeter. Nor are there firewall on the hosts I am trying to reach, and as noted, other devices, regardless of IP, can successfully communicate.

It looks as if the Steam Deck is treating the network as if it has a /24 subnet address.

Any suggestions welcome!
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