how to make en0 2nd ip work

[diadal]

please this network en0 when I connect client to 172.211.79.132 is not working but when client connected to 172.211.79.111 please any idea how to fix this

en0: flags=8763<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	options=50b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV,CHANNEL_IO>
	ether 21:cd:b1:a9:84:8v 
	inet6 fe70::425:c750:9a15:bn3b%en0 prefixlen 64 secured scopeid 0x8 
	inet 172.211.79.111 netmask 0xffffff00 broadcast 172.211.79.255
	inet 172.211.79.132 netmask 0xffffff00 broadcast 172.211.79.255
	nd6 options=201<PERFORMNUD,DAD>
	media: autoselect (1000baseT <full-duplex>)
	status: active