在IPhone上获取DNS服务器IP [英] Getting DNS server IP on IPhone

问题描述

我想使用 libresolv 框架获得我的dns服务器IP，但我得到的是0.0.0.0

   - （void）getDns 
 {
 res_init（）; 
 
 for（int i = 0; i  {
 printf（％s，inet_ntoa（_res.nsaddr_list [i] .sin_addr））; 
 
} 
} 
  

我的代码在这里有什么问题？

感谢

编辑

$ b b

尝试在SO的其他问题中使用代码，但这是我在主机是apple.com时得到的

  2011-03-16 15：07：21.689 MobileMax [5876：207]已解决0：< 17.149.160.49> 
 2011-03-16 15：07：21.691 MobileMax [5876：207]分辨率1：< 17.251.200.70> 
 2011-03-16 15：07：21.691 MobileMax [5876：207]分辨率2：< 17.112.152.57> 
  

运行命令时： cat /etc/resolv.conf
我得到 nameserver 10.0.0.138 这是我想要的。

我也试过这个，但仍然得到0.0.0.0响应。

  u_char buf [NS_PACKETSZ]; 
 int responseLen; 
 
 res_query（www.google.com，ns_c_in，ns_t_ns，buf，sizeof（buf））; 
  

解决方案

获取DNS服务器地址。不要忘记链接libresolv.lib

  #include< arpa / inet.h> ; 
 #include< ifaddrs.h> 
 #include< resolv.h> 
 #include< dns.h> 
 
  - （NSString *）getDNSServers 
 {
 //不要忘记链接libresolv.lib 
 NSMutableString * addresses = [[NSMutableString alloc] initWithString：@DNS地址\\\
]; 
 
 res_state res = malloc（sizeof（struct __res_state））; 
 
 int result = res_ninit（res）; 
 
 if（result == 0）
 {
 for（int i = 0; i< res-> nscount; i ++）
 {
 NSString * s = [NSString stringWithUTF8String：inet_ntoa（res-> nsaddr_list [i] .sin_addr）]; 
 [addresses appendFormat：@％@ \\\
，s]; 
 NSLog（@％@，s）; 
} 
} 
 else 
 [addresses appendString：@res_init result！= 0]; 
 
返回地址; 
} 
  

I'm trying to get the my dns server IP using using libresolv framework , but all I get is "0.0.0.0"

-(void) getDns
{
    res_init();

    for (int i=0;i<MAXNS;i++)
    {       
        printf("%s",inet_ntoa(_res.nsaddr_list[i].sin_addr));

    }
}

Anything wrong with my code here ?

Thanks

Edit

Tried to use the code in SO's other question, but this is what I get when the host is "apple.com"

2011-03-16 15:07:21.689 MobileMax[5876:207] RESOLVED 0:<17.149.160.49>
2011-03-16 15:07:21.691 MobileMax[5876:207] RESOLVED 1:<17.251.200.70>
2011-03-16 15:07:21.691 MobileMax[5876:207] RESOLVED 2:<17.112.152.57>

While when running the command : cat /etc/resolv.conf I get nameserver 10.0.0.138 which is what I want.

Any idea how to get that ?

Edit2

I tried this as well, but still getting the "0.0.0.0" response.

u_char buf[NS_PACKETSZ];
int responseLen;             

    res_query("www.google.com",ns_c_in,ns_t_ns,buf,sizeof(buf));

解决方案

Try below code to get DNS Server Address . Don't forget to link libresolv.lib

    #include <arpa/inet.h>
    #include <ifaddrs.h>
    #include <resolv.h>
    #include <dns.h>

    - (NSString *) getDNSServers
    {
    // dont forget to link libresolv.lib
    NSMutableString *addresses = [[NSMutableString alloc]initWithString:@"DNS Addresses \n"];

    res_state res = malloc(sizeof(struct __res_state));

    int result = res_ninit(res);

    if ( result == 0 )
    {
        for ( int i = 0; i < res->nscount; i++ )
        {
            NSString *s = [NSString stringWithUTF8String :  inet_ntoa(res->nsaddr_list[i].sin_addr)];
            [addresses appendFormat:@"%@\n",s];
            NSLog(@"%@",s);
        }
    }
    else
        [addresses appendString:@" res_init result != 0"];

    return addresses;
}

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