问题描述
我正在尝试使用Arduino以太网库构建一个小项目,但是我遇到了一个奇怪的DNS问题:
I'm trying to build a little project using the Arduino Ethernet library, but I'm having a weird DNS issue:
它无法解析我的网络本地的任何域名,但是解析公共域名没有问题.
我的网络上没有其他系统对这些本地域名有问题.似乎只是Arduino.
No other system on my network has problems with these local domain names. It just seems to be the Arduino.
这是我正在使用的:
- Arduino Uno R3
- Arduino以太网盾R3
- Arduino IDE 1.0.3
- Asus RT-N66U路由器(提供DNS服务器)
- Arduino Uno R3
- Arduino Ethernet Shield R3
- Arduino IDE 1.0.3
- Asus RT-N66U Router (provides the DNS server)
这是我的测试草图:
#include <SPI.h>
#include <Ethernet.h>
#include <Dns.h>
#include <EthernetUdp.h>
byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
EthernetClient client;
void setup() {
Serial.begin(9600);
if (Ethernet.begin(mac) == 0) {
Serial.println("Failed to configure Ethernet using DHCP");
while(true);
}
delay(1000);
Serial.println("connecting...");
DNSClient dnsClient;
// Router IP address
byte dnsIp[] = {192, 168, 11, 1};
dnsClient.begin(dnsIp);
// Regular DNS names work...
IPAddress ip1;
dnsClient.getHostByName("www.google.com", ip1);
Serial.print("www.google.com: ");
Serial.println(ip1);
// However local ones defined by my router do not (but they work fine everywhere else)...
IPAddress ip2;
dnsClient.getHostByName("Tycho.localnet", ip2);
Serial.print("Tycho.localnet: ");
Serial.println(ip2);
}
void loop() {
}
这是它的输出(第二个IP地址不正确):
Here's its output (the second IP address is incorrect):
connecting...
www.google.com: 74.125.227.84
Tycho.localnet: 195.158.0.0
以下是从连接到同一网络的Linux机器提供的正确信息:
Here's the correct information given from a Linux machine connected to the same network:
$ nslookup www.google.com
Server: 192.168.11.1
Address: 192.168.11.1#53
Non-authoritative answer:
Name: www.google.com
Address: 74.125.227.80
Name: www.google.com
Address: 74.125.227.84
Name: www.google.com
Address: 74.125.227.82
Name: www.google.com
Address: 74.125.227.83
Name: www.google.com
Address: 74.125.227.81
$ nslookup Tycho.localnet
Server: 192.168.11.1
Address: 192.168.11.1#53
Name: Tycho.localnet
Address: 192.168.11.2
这是怎么回事?
推荐答案
我不知道您是否已经找到解决方案,但以防万一:
I don't know if you've already found a solution, but just in case:
inet_aton
中有一个缺陷,它是DNS库的一部分:
There's a defect in inet_aton
which is part of the DNS library:
这应该将字符串IP地址转换为IPAddress类型.
This is supposed to convert a string IP address to the IPAddress type.
要发现它会测试字符串中的每个字符是否为数字:
To find out it tests each character in the string for numerals:
while (*p &&
( (*p == '.') || (*p >= '0') || (*p <= '9') ))
,但任何字母字符均匹配*p >= '0'
but any alphabetic character matches *p >= '0'
应该是:
while (*p &&
( (*p == '.') || ((*p >= '0') && (*p <= '9')) ))
您需要在Dns.cpp
中进行更改.
这篇关于Arduino本地DNS问题的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!