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?
