如何查询服务器并获取MX,A,NS记录

Question

我正在尝试获取A,MX和NS A服务器记录,如下所示:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <resolv.h>
#include <netdb.h>

#define N 4096

int main (int argc, char *argv[])
{
    u_char nsbuf[N];
    char dispbuf[N];
    ns_msg msg;
    ns_rr rr;
    int i, l;

    if (argc < 2) {
        printf ("Usage: %s <domain>\n", argv[0]);
        exit (1);
    }

    // HEADER
    printf("Domain : %s\n", argv[1]);
    // ------

    // A RECORD
    printf("A records : \n");
    l = res_query(argv[1], ns_c_any, ns_t_a, nsbuf, sizeof(nsbuf));
    if (l < 0)
    {
      perror(argv[1]);
    }
    ns_initparse(nsbuf, l, &msg);
    l = ns_msg_count(msg, ns_s_an);
    for (i = 0; i < l; i++)
    {
      ns_parserr(&msg, ns_s_an, 0, &rr);
      ns_sprintrr(&msg, &rr, NULL, NULL, dispbuf, sizeof(dispbuf));
      printf("\t%s \n", dispbuf);
    }
    //------------


    // MX RECORD
    printf("MX records : \n");
    l = res_query(argv[1], ns_c_any, ns_t_mx, nsbuf, sizeof(nsbuf));
    if (l < 0)
    {
      perror(argv[1]);
    }
    else
    {
#ifdef USE_PQUERY
      /* this will give lots of detailed info on the request and reply */
      res_pquery(&_res, nsbuf, l, stdout);
#else
      /* just grab the MX answer info */
      ns_initparse(nsbuf, l, &msg);
      l = ns_msg_count(msg, ns_s_an);
      for (i = 0; i < l; i++)
      {
        ns_parserr(&msg, ns_s_an, i, &rr);
        ns_sprintrr(&msg, &rr, NULL, NULL, dispbuf, sizeof(dispbuf));
        printf ("\t%s\n", dispbuf);
      }
#endif
    }
    // ---------

    // NS RECORD
    printf("NS records : \n");
    l = res_query(argv[1], ns_c_any, ns_t_ns, nsbuf, sizeof(nsbuf));
    if (l < 0)
    {
      perror(argv[1]);
    }
    ns_initparse(nsbuf, l, &msg);
    l = ns_msg_count(msg, ns_s_an);
    for (i = 0; i < l; i++)
    {
      ns_parserr(&msg, ns_s_an, 0, &rr);
      ns_sprintrr(&msg, &rr, NULL, NULL, dispbuf, sizeof(dispbuf));
      printf("\t%s \n", dispbuf);
    }
    // ---------
    return 0;
}

根据要求收到很多相同的,即相同的A记录.与NS记录相同.我究竟做错了什么？示例:

Domain : mail.ru
A records :
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
        mail.ru.                22S IN A        94.100.191.207
MX records :
        mail.ru.                1m57s IN MX     10 mxs.mail.ru.
NS records :
        mail.ru.                1m50s IN NS     ns.mail.ru.
        mail.ru.                1m50s IN NS     ns.mail.ru.
        mail.ru.                1m50s IN NS     ns.mail.ru.
        mail.ru.                1m50s IN NS     ns.mail.ru.
        mail.ru.                1m50s IN NS     ns.mail.ru.
        mail.ru.                1m50s IN NS     ns.mail.ru.

请帮忙.

Answer 1

在这个电话中:

  ns_parserr(&msg, ns_s_an, 0, &rr);

第三个参数是要检索的记录的索引.所以在你的情况下它应该是:

  ns_parserr(&msg, ns_s_an, i, &rr);

刚尝试使用那个小修补程序的代码,它按预期工作:

Domain : mail.ru
A records : 
    mail.ru.        5S IN A     94.100.191.248 
    mail.ru.        5S IN A     94.100.191.249 
    mail.ru.        5S IN A     94.100.191.250 
    mail.ru.        5S IN A     94.100.191.201 
    mail.ru.        5S IN A     94.100.191.202 
    mail.ru.        5S IN A     94.100.191.203 
    mail.ru.        5S IN A     94.100.191.204 
    mail.ru.        5S IN A     94.100.191.205 
    mail.ru.        5S IN A     94.100.191.206 
    mail.ru.        5S IN A     94.100.191.207 
    mail.ru.        5S IN A     94.100.191.208 
    mail.ru.        5S IN A     94.100.191.209 
    mail.ru.        5S IN A     94.100.191.210 
    mail.ru.        5S IN A     94.100.191.241 
    mail.ru.        5S IN A     94.100.191.242 
    mail.ru.        5S IN A     94.100.191.243 
    mail.ru.        5S IN A     94.100.191.244 
    mail.ru.        5S IN A     94.100.191.245 
    mail.ru.        5S IN A     94.100.191.246 
    mail.ru.        5S IN A     94.100.191.247 
MX records : 
    mail.ru.        7m14s IN MX 10 mxs.mail.ru.
NS records : 
    mail.ru.        3m35s IN NS ns2.mail.ru. 
    mail.ru.        3m35s IN NS ns.mail.ru. 
    mail.ru.        3m35s IN NS ns4.mail.ru. 
    mail.ru.        3m35s IN NS ns5.mail.ru. 
    mail.ru.        3m35s IN NS ns1.mail.ru. 
    mail.ru.        3m35s IN NS ns3.mail.ru.