I use freertos version 5.0.2 and lwip.

target board program following code for server

1. calling founction

void vBasicWEBServer( void *pvParameters ) // basicweb.c
{
unsigned char pcMessageToExchange[] = "\n init socket\r\n";

struct ip_addr xIpAddr, xNetMast, xGateway;
extern err_t ethernetif_init( struct netif *netif );

/* Parameters are not used - suppress compiler error. */
( void ) pvParameters;

/* Create and configure the EMAC interface. */
IP4_ADDR( &xIpAddr, emacIPADDR0, emacIPADDR1, emacIPADDR2, emacIPADDR3 );
IP4_ADDR( &xNetMast, emacNET_MASK0, emacNET_MASK1, emacNET_MASK2, emacNET_MASK3 );
IP4_ADDR( &xGateway, emacGATEWAY_ADDR0, emacGATEWAY_ADDR1, emacGATEWAY_ADDR2, emacGATEWAY_ADDR3 );
netif_add( &EMAC_if, &xIpAddr, &xNetMast, &xGateway, NULL, ethernetif_init, tcpip_input );

/* make it the default interface */
netif_set_default( &EMAC_if );

/* bring it up */
netif_set_up(&EMAC_if);


vSerialPutString( 0, pcMessageToExchange, strlen( pcMessageToExchange ) );
/* Initialize HTTP */
// httpd_init(); //kcs

kcs_server(); // kcs


/* Nothing else to do. No point hanging around. */
vTaskDelete( NULL );
}


void kcs_server() // httpd.c
{

struct tcp_pcb *pcb;

pcb = tcp_new();

tcp_bind(pcb, IP_ADDR_ANY,2000);

tcp_arg(pcb,NULL);

pcb = tcp_listen(pcb);

tcp_accept( pcb, helloworld_accept);
}

void helloworld_accept( void *arg, struct tcp_pcb *pcb, err_t err) // kcs
{

int i,j;

vSerialPutString( 0, "accept\r\n", 10 );


vSerialPutString( 0, "read\r\n", 8 );
tcp_err(pcb,conn_err); // 2010.3.4 kim
tcp_recv(pcb, kcs_receive);


for(j = 0; j < 1; j++)
{
vSerialPutString( 0, "write\r\n", 9 );
tcp_write(pcb, GREETING, strlen(GREETING),1);
for( i = 0; i < 100;i++) ;
}



}

err_t kcs_receive(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) // kcs
{
int i;

vSerialPutString( 0, "receive\r\n", 11);

if( p != NULL)
{

tcp_recved(pcb,p->tot_len); // add kcs 2010.3.4



vSerialPutString( 0, p->payload, p->tot_len );
err = tcp_write(pcb,p->payload,p->tot_len ,1);
}
else if( err == ERR_OK)
{
vSerialPutString( 0, "socket close\r\n", 16 );
tcp_close(pcb);
}

err = tcp_write(pcb,p->payload,p->len,1);

}


Above code run 8 times packet and ping reply, but don't run 9 times. and ping don't reply
why did it run?

Sorry, but I have no idea and cannot read the code very easily. I would guess either a problem in your Ethernet driver, or you are not freeing memory buffers and so are simply running out of buffers. I think you would have to switch on some of the debugging/logging in lwIP to see why it stops running.

Also, the lwIP mailing list is a very active place to get lwIP specific support.

Regards.