删除dhcp然后重新加载
no ip dhcp polocy POLICY50 1
no ip dhcp pool DHCP50
no ip pool dhcp50
ip pool DHCP50
range 10.170.3.2 10.170.3.254 255.255.255.0
exit
ip DHCP pool DHCP50
ip-pool DHCP50
default-router 10.170.3.1
dns-server 60.191.134.126 60.192.134.206
exit
ip DHCP policy policy50 1 dhcp-pool DHCP50