发现服务器上开启的TCP服务

用netstat -a

编程嘛，自己做一个端口扫描器

#include <libnet.h>
#include <pcap.h>
#include "hacking.h"

#define MAX_EXISTING_PORTS 30

void caught_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
int set_packet_filter(pcap_t *, struct in_addr *, u_short *);

struct data_pass {
int libnet_handle;
u_char *packet;
};

int main(int argc, char *argv[]) {
struct pcap_pkthdr cap_header;
const u_char *packet, *pkt_data;
pcap_t *pcap_handle;
char errbuf[PCAP_ERRBUF_SIZE]; // Same size as LIBNET_ERRBUF_SIZE
char *device;
u_long target_ip;
int network, i;
struct data_pass critical_libnet_data;
u_short existing_ports[MAX_EXISTING_PORTS];

if((argc < 2) || (argc > MAX_EXISTING_PORTS+2)) {
if(argc > 2)
printf("Limited to tracking %d existing ports.\n&quo