As a beginner, I use WinBox v3.19+RouterOS 6.45.6 on RB450Gx4.

After I reset default configuration, using quicksetup for basic setup and enable VPN access, I found the vpn ip pool is 192.168.89.2-192.168.89.255. Is that supposed to be correct? As far as I remembered at school back in 2000, 255 is the broadcast address.

192.168.89.255 is indeed a broadcast address and i ve never seen a pool to include that.. its wrong... However i never use quicksetup .. perhaps its a bug or something...

255 is a broadcast address when the subnet's broadcast address falls there (i.e., x.x.x.255/24)

VPNs and (more specifically) PPP, uses point-to-point addressing. There is no network, nor broadcast address at play.

Savage talks about CIDR /32 which is the point to point addressing... for example 192.168.88.2/32 is just the address 192.168.88.2, just one address, one host...

Personally to avoid confusion i would never use an address with .255...

Also strictly speaking the address 192.168.88.2/32 has a network address of 192.168.88.2, a broadcast address of 192.168.88.2 and one host which is 192.168.88.2 ...

Oh thanks everyone I get it.