PPP will "normally" allocate an IP address with a subnet mask of 255.255.255.255.
PPP is Point to Point Protocol - the interfaces don't belong to a "subnet" in the sense that LAN interfaces do. PPP is not a broadcast protocol.
Static IP on PPP "normally" means the PPP server always allocates the same IP address.
Here's what the pppoe interface on one of my pfSense systems:
$ ifconfig pppoe0
pppoe0: flags=88d1 <up,pointopoint,running,noarp,simplex,multicast>metric 0 mtu 1492
inet 203.144.23.199 –> 121.50.212.9 netmask 0xffffffff
inet6 fe80::219:e0ff:fe68:314b%pppoe0 prefixlen 64 scopeid 0xa
nd6 options=3 <performnud,accept_rtadv>$</performnud,accept_rtadv></up,pointopoint,running,noarp,simplex,multicast>
@stilez:
Connectivity here need PPPoE (to handle CHAP) and also need the interface to 'know' its subnet.
Why does the interface need to know its subnet?