Hi Prasad
I would suggest you check the lwip_ping demo for how to configure IP, netmask, gw.
Please refer to the lwip_ping demo for more details
SDK_2.2_FRDM-K66F\boards\frdmk66f\demo_apps\lwip\lwip_ping\bm\lwip_ping_bm.c
IP4_ADDR(&fsl_netif0_ipaddr, configIP_ADDR0, configIP_ADDR1, configIP_ADDR2, configIP_ADDR3);
IP4_ADDR(&fsl_netif0_netmask, configNET_MASK0, configNET_MASK1, configNET_MASK2, configNET_MASK3);
IP4_ADDR(&fsl_netif0_gw, configGW_ADDR0, configGW_ADDR1, configGW_ADDR2, configGW_ADDR3);
lwip_init();
netif_add(&fsl_netif0, &fsl_netif0_ipaddr, &fsl_netif0_netmask, &fsl_netif0_gw, NULL, ethernetif_init,
ethernet_input);
netif_set_default(&fsl_netif0);
netif_set_up(&fsl_netif0);
Regards
Daniel