Multi-LAN with same gateway

[josesilva]

hi,

if i configure 2 or more LANs with the same gateway, and i'm using the same subnet in all of them will it have the same broadcast domain?

thanks

[Guest]

Why assign multiple interfaces to serve the same network space?  Yes, all machines within the same logical network will share the same broadcast domain, which is another reason not to segregate these network segments on different cards.

[josesilva]

So in the end, it will behave almost like a hub? The use case is If you want to spare a switch and you have a free network card for example..

thanks for your reply.

[jimp]

Then you bridge the interfaces together, not assign them IPs in the same subnet.

[josesilva]

Ok, i'm migrating a flat network and using a pfsense as firewall.

i have a 3 interfaces box, one for wan, two for "lan".

For now i'm using both lans in the same subnet, with same ip. I do assign both ports (interfaces) the same IP. I do it to make easier the network configuration. The DHCP scope, for instance, provides one gateway for all hosts on my network.  So it works like a charm, the problem is that in the end, this two ports are working like a hub. So the solution would be to enable "bridging" in both interfaces, right? But with bridging, can i still using one IP to both interfaces? Or should i create different subnets and assign different ips to both interfaces and keep both port in different subnets? The problem with this option is that it brings an undesirable complexity.

@jimp:

Then you bridge the interfaces together, not assign them IPs in the same subnet.