我已经使用 C# 和 PCAP 创建了一个 DNS 请求。我使用wireshark检查了请求。但没有回应。
我比较了有响应的 DNS 请求。标志和 DNS 查询值相同。
我无法弄清楚为什么 dns 解析器没有发送响应。请帮我。
谢谢你。
我的数据包生成方法：
private Packet getPacket(string s, string d,string domain)
{
Random r = new Random();
EthernetLayer ethernetLayer =
new EthernetLayer
{
Source = new MacAddress("00:0C:29:E5:FA:36"),
Destination = new MacAddress("00:0c:29:e5:fa:36"),
EtherType = EthernetType.None, // Will be filled automatically.
};
IpV4Layer ipV4Layer =
new IpV4Layer
{
Source = new IpV4Address(s),
CurrentDestination = new IpV4Address(d),
Fragmentation = IpV4Fragmentation.None,
HeaderChecksum = null, // Will be filled automatically.
Identification = 123,
Options = IpV4Options.None,
Protocol = null, // Will be filled automatically.
Ttl = 100,
TypeOfService = 0,
};
UdpLayer udpLayer =
new UdpLayer
{
SourcePort =ushort.MaxValue,
DestinationPort = 53,
Checksum = null, // Will be filled automatically.
CalculateChecksumValue = true,
};
DnsLayer dnsLayer =
new DnsLayer
{
Id = ushort.Parse(r.Next(0,99999).ToString()),
IsResponse = false,
OpCode = DnsOpCode.Query,
IsAuthoritativeAnswer = false,
IsTruncated = false,
IsRecursionDesired = true,
IsRecursionAvailable = false,
FutureUse = false,
IsAuthenticData = false,
IsCheckingDisabled = false,
ResponseCode = DnsResponseCode.NoError,
Queries = new[]
{
new DnsQueryResourceRecord(new DnsDomainName("col.stc.s-msn.com"),
DnsType.A,
DnsClass.Internet),
},
Answers = null,
Authorities = null,
Additionals = null,
DomainNameCompressionMode = DnsDomainNameCompressionMode.All,
};
PacketBuilder builder = new PacketBuilder(ethernetLayer, ipV4Layer, udpLayer, dnsLayer);
return builder.Build(DateTime.Now);
}
}
这是我的数据包发送功能：
private static void performRequest(LivePacketDevice device)
{
using (PacketCommunicator communicator = device.Open(100,PacketDeviceOpenAttributes.Promiscuous,1000))
{
for (int i = 0; i < threadCount; i++)
{
Thread requester= new Thread(() =>
{
try
{
Program p = new Program();
Random r = new Random();
string resolve = resolvers[r.Next(0, resolvers.Count-1)].ToString();
communicator.SendPacket(p.getPacket(destinationIP.ToString(), resolve, domainName));
p = null;
r = null;
}
catch (Exception ex) { Console.WriteLine(ex.Message); }
});
requester.Start();
Thread.Sleep(1000);
}
}
}