Where is the missing IP ?

vipi

Hi
Trying to understand basics, I wander why in subnet topology mode for a /24 vpn where .0 is the network, .1 the server, .255 being the broadcast and the pool base is .2, then size displays 252 instead of 253?
Same for a smaller /28 : IFCONFIG POOL: base=10.0.4.2 size=12 instead of 13
Same for a smaller /29 : IFCONFIG POOL: base=10.0.4.2 size=4 instead of 5

I checked clients are allocated IP's starting at base=.2
So, maybe BR-1 has special function or is reserved, or is it only a bad computation of the displayed pool size which is only cosmetic error?

Thanks