Getting Bad masks on sub-interfaces?

MrXpert

I've been trying to configure IP addresses on the sub-interfaces on a router. This is for the purpose of setting up a router on a stick. I've done it many times before and it works fine but this time around I thought i'd try it with VLSM in mind which i have only recently read about (actually watched via cbt nuggets). Somewhere I am clearly going wrong. On my first attempt at trying to set the IP address for a sub interface I got a bad mask error message

Here's some output I got from the command entered on the router

NOTTS-R1(config)#int fa0/0.250

%LINK-5-CHANGED: Interface FastEthernet0/0.250, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0.250, changed state to up
NOTTS-R1(config-subif)#
NOTTS-R1(config-subif)#encap
NOTTS-R1(config-subif)#encapsulation dot1q 250 ?
native Make this as native vlan
<cr>
NOTTS-R1(config-subif)#encapsulation dot1q 250
NOTTS-R1(config-subif)#ip address 172.16.1.0 255.255.255.240
Bad mask /28 for address 172.16.1.0

I then also tried it on the normal fa0/0 interface

NOTTS-R1(config)#int fa0/0
NOTTS-R1(config-if)#ip address 172.16.0.0 255.255.255.128
Bad mask /25 for address 172.16.0.0

It's probably something abvious I am missing or just not seeing.Anyone help me please?

ColbyG

You're trying to assign an address to the NID. Make it .1, not .0.