英文:
Golang UDP Server only recieving locally sent packets
问题
我已经写了一个在Go中监听端口666的UDP服务器，并且似乎只接收到本地发送的数据包。为了确认流量，我一直在使用以下命令：
sudo tcpdump -n udp dst port 666
这是我简化后的服务器代码：
import "net"
func startServer() {
// 绑定端口。
ServerAddr, err := net.ResolveUDPAddr("udp", "localhost:666")
if err != nil {
fmt.Println("Error binding port!")
}
ServerConn, _ := net.ListenUDP("udp", ServerAddr)
defer ServerConn.Close()
buf := make([]byte, 1024)
for {
// 接收一个UDP数据包并将其解组为protobuf。
n, _, _ := ServerConn.ReadFromUDP(buf)
fmt.Println("Packet received!")
// 处理buf中的数据。
}
}
如果我在运行服务器的机器上使用以下命令：
echo -n "foo" | nc -4u -w1 127.0.0.1 666
那么服务器将接收到该数据包，并打印出消息（tcpdump不显示任何输出）。
然而，如果我从网络上的另一台计算机上运行以下命令：
echo -n "foo" | nc -4u -w1 192.168.1.134 666
然后，虽然tcpdump报告接收到一个数据包（15:05:43.634604 IP 192.168.1.113.59832 > 192.168.1.134.666: UDP, length 9，确认我正确获取了IP地址），但Go服务器没有响应。
我需要做一些特殊的操作才能使Go响应非本地请求吗？
英文:
I've written a UDP Server in Go(listens on port 666), and it seems to be only receiving packets that were sent locally. To confirm traffic, I have been using:
sudo tcpdump -n udp dst port 666
My(abbreviated) server code:
import "net"
func startServer() {
// Bind the port.
ServerAddr, err := net.ResolveUDPAddr("udp", "localhost:666")
if err != nil {
fmt.Println("Error binding port!")
}
ServerConn, _ := net.ListenUDP("udp", ServerAddr)
defer ServerConn.Close()
buf := make([]byte, 1024)
for {
// Recieve a UDP packet and unmarshal it into a protobuf.
n, _, _ := ServerConn.ReadFromUDP(buf)
fmt.Println("Packet received!")
// Do stuff with buf.
}
}
If, from the machine the server is running on, I use:
echo -n “foo” | nc -4u -w1 127.0.0.1 666
then the server receives that packet, and prints the message(and tcpdump shows no output).
However, if I run the following from another computer on the network:
echo -n “foo” | nc -4u -w1 192.168.1.134 666
Then, while tcpdump reports a packet being received (15:05:43.634604 IP 192.168.1.113.59832 > 192.168.1.134.666: UDP, length 9 confirming I got the IP address right), the Go server does not respond.
Is there something special I need to do to make Go respond to non-local requests?
答案1
得分: 3
只需在任何地址上进行监听，你只会监听本地主机。
ServerAddr, err := net.ResolveUDPAddr("udp", ":666")
英文:
Just listen on any address, you're listening on localhost only.
ServerAddr, err := net.ResolveUDPAddr("udp", ":666")
答案2
得分: 1
它正在执行你告诉它要做的事情：在127.0.0.1上监听。如果你想让它监听所有接口，你需要指定0.0.0.0。
不要问我如何在Go中实现这个。
英文:
It's doing what you told it to do: listen at 127.0.0.1. If you want it to listen at all interfaces, you have to specify 0.0.0.0.
Don't ask me how that's done in Go.
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