- args="-l /tmp/dhcp.leases -K -F $(int2ip $start),$(int2ip $end),$(int2ip $netmask),12h"
+ wanproto=$(nvram get wan_proto)
+ [ -z "$wanproto" -o "$wanproto" = "none" ] || wanif=$(nvram get wan_ifname)
+
+ args="-K -F $(int2ip $start),$(int2ip $end),$(int2ip $netmask),12h ${wanif:+-I ${wanif} }"