I shared another post here with how subnetting works. Basically, if you start with 192.168.1.254 on a /24 for your gateway and move to a /23, your usable range goes from 192.168.1.1-192.168.1.254 to 192.168.0.1-192.168.1.254.
In this situation, the gateway address stays the same and since the /24 is contained within the /23, they can still connect to the gateway and keep working while you migrate things. The only thing they cannot talk to is clients in the 192.168.0.0/24 space until they pull new DHCP or have their static address updated. As such, it can make future expansion easier, if necessary.
If you used 192.168.1.1/24 as the gateway initially, you’ll notice that in this same expansion plan it’s now smack in the middle of the subnet in a /23. Is that the end of the world? No, but it looks like shit and complicates things if you did something like I usually do and allocate certain “sections” of the subnet to non-DHCP space. Also, now you need to manage two DHCP pools, one below 192.168.1.1 and one above it. It’s one of those small things that compounds with each bandaid until you’re dying by a thousand cuts.
I’m theory you would design your network with a large enough subnet from the get-go for expansion, but sometimes you screw up, so habits like this can make those screw ups less painful.
What am I missing here?
192.168.1.1/24 would also be a valid gateway for a /23, with the benefit of not having a gateway in the middle of your /23 network?
I feel like this example is a greater justification for putting the gateway on the network/CIDR + 1, like a civilized person.
I shared another post here with how subnetting works. Basically, if you start with 192.168.1.254 on a /24 for your gateway and move to a /23, your usable range goes from 192.168.1.1-192.168.1.254 to 192.168.0.1-192.168.1.254.
In this situation, the gateway address stays the same and since the /24 is contained within the /23, they can still connect to the gateway and keep working while you migrate things. The only thing they cannot talk to is clients in the 192.168.0.0/24 space until they pull new DHCP or have their static address updated. As such, it can make future expansion easier, if necessary.
If you used 192.168.1.1/24 as the gateway initially, you’ll notice that in this same expansion plan it’s now smack in the middle of the subnet in a /23. Is that the end of the world? No, but it looks like shit and complicates things if you did something like I usually do and allocate certain “sections” of the subnet to non-DHCP space. Also, now you need to manage two DHCP pools, one below 192.168.1.1 and one above it. It’s one of those small things that compounds with each bandaid until you’re dying by a thousand cuts.
I’m theory you would design your network with a large enough subnet from the get-go for expansion, but sometimes you screw up, so habits like this can make those screw ups less painful.
Bleh, gotchu, I was getting the bit boundary wrong (192.168.0.0/24 > 192.168.0.0/23; NOT 192.168.1.0. that’s not how bits work)