?? ioc is irelevant here. Network stack need understand how it works.
Show your ping command ... have you DHCP server is your RJ45 cable ?
Is your main.h settings ?
/* Exported types ------------------------------------------------------------*/
/* Exported constants --------------------------------------------------------*/
#define USE_DHCP /* enable DHCP, if disabled static address is used*/
/*Static IP ADDRESS*/
#define IP_ADDR0 (uint8_t) 192
#define IP_ADDR1 (uint8_t) 168
#define IP_ADDR2 (uint8_t) 0
#define IP_ADDR3 (uint8_t) 10
this is from LWip example 429