> Network: 3.2.0.0 Netmask: 255.255.254.0 (/23) Broadcast: 3.2.1.255 In classful addressing it is a network 3.0.0.0 with a netmask 255.0.0.0 (/8). In a classle

> Network: 3.2.0.0 Netmask: 255.255.254.0 (/23) Broadcast: 3.2.1.255 In classful addressing it is a network 3.0.0.0 with a netmask 255.0.0.0 (/8). In a classless, it is whatever has been advertised to me. > Public BGP requires /24 or wider, and /24 cannot contain .0 or .255 as a valid IP, so the next widest is /23, which can contain even-numbered .x.255 and .x+1.0. If you're doing this on an internal network that permits narrower subnets, the narrowest available would be a /30, based (irregularly) on either .1.254 or .1.255: It does not. You can advertise whatever the hell you want. What matters is what the other side would accept. It used to be that no one would accept anything less specific than /24 in a class C address space, /16 in a class B address space and /8 in a class A address space because the internet ran on AGS and maybe AGS+ which just did not have enough memory to do real classless. That stopped around the time GlobalCrossing showed up (or maybe around the time Mr V did terrible things while running AS7007). But anyway, ten years ago /27s are definitely accepted routes by those that comprised over 80% of the gloabal internet by the single origin prefixes.