Is 255.255.255.228 a valid subnet?

[Mister Natural]

I'm replacing an old firewall and when I was checking the settings I saw the subnet on the WAN is 255.255.255.228. This seems strange to me. Internet works at that location but wondering if it should be 248.

 

[/usr/home]

No. 224 and 240 are but not 228.

 

[vitalym]

Generally it's .248 but .0 would work too
.228 is not a valid subnet mask so it's strange the firewall allowed you to use it

 

[Mister Natural]

I changed it to 248 and things are working so leaving it at that. Thanks.

 

[/usr/home]

How many hosts are behind the firewall?

 

[trick0502]

the only valid subnet masks: 0, 128, 192, 224, 240, 248, 252, 254

00000000=0
10000000=128
11000000=192
11100000=224
11110000=240
11111000=248
11111100=252
11111110=254

 

[Mister Natural]

I manage firewall/routers for around 50 different locations and I'd say 90% or more are 248 on the WAN.