bridging 2 networks...Subnet mask question

[Cr0nJ0b]

I'm really confused on the whole subnet mask stuff. I've read a bunch but it just confuses me more. I know that I need something like 255.255.255.0 for a full class C network, but I'm bridging 2 networks together. 192.168.1.0/24 and 192.168.2.0/24. I sort of assumed that if I put them both on the same switch and link them together I should be able to see the other computers...assuming that my subnet mask is something broader than 255.255.255.0. So I tried 255.255.0.0 and 255.255.254.0..

Then I noticed that one of my systems has no issues with hitting computers on 192.168.2.0/24 even though it has a mask of 255.255.255.0

Boy, I'm confused...really.

essentially what I'm trying to do is this.

Network A -- Internal LAN 192.168.1.0/24
Network B -- WAN interface to cable modem
Network C -- Internal LAN 192.168.2.0/24
Network D -- WAN interface

I have a couple of firewalls...

first network:

Internet (B) Internet (D)
^ ^
| |
A <--->router FW <-->router FW <---->C

The reason i'm doing this is because C is all my wifi stuff and because a lot of it's bridged, I'm just going to run a captive portal. But, there are a few clients that I want to get in to network A. I don't plan to use VPN or anything more fancy than mac filtering and pass through to get people from C to internet, but since C is on a different subnet what does the mask need to be at the various links?

thanks

 

[Nuwave]

Essentially What you are trying to do is make one big subnet so that all of your devices are in the same subnet. That could be accomplished by re IPing all your devices so that they are all in 192.168.1.0/24 or 192.168.2.0/24

What you attempted to do is change the mask which would essentially put both of those IP ranges in the same subnet. Except 192.168.1.0/23 is not in the same subnet as 192.168.2.0/23. When using a /23 mask you get the following IP address ranges. Note the 3rd octect

192.168.0.0 - 192.168.1.255
192.168.2.0 - 192.168.3.255
192.168.4.0 - 192.168.5.255
.....
192.168.254.0 - 192.168.255.255


So without routing stuff addressed as 192.168.1.x cannot communicate with stuff addressed as 192.168.2.x.

You could however change the mask to a /22 wich would encompass all of the IP's you are dealing with

192.168.0.0 - 192.168.3.255


With that said I don't think you want to do that at all.

I think you want to set up routing.