arp ping works.

Makefile

board/inteno/ex300/Makefile

board/inteno/ex300/httpd.c

include/common.h

include/configs/ex300.h

include/lwip/app/dhcpserver.h

include/lwip/app/espconn.h

include/lwip/app/espconn_tcp.h

include/lwip/app/espconn_udp.h

include/lwip/app/ping.h

include/lwip/app/user_interface.h

include/lwip/arch/cc.h

include/lwip/arch/perf.h

include/lwip/ipv4/lwip/autoip.h

include/lwip/ipv4/lwip/icmp.h

include/lwip/ipv4/lwip/igmp.h

include/lwip/ipv4/lwip/inet.h

include/lwip/ipv4/lwip/inet_chksum.h

include/lwip/ipv4/lwip/ip.h

include/lwip/ipv4/lwip/ip_addr.h