[英]netstat does not show listening port of udp server?
I have the following udp server: 我有以下udp服务器:
/************* UDP SERVER CODE *******************/
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
int main(){
int udpSocket, nBytes;
char buffer[1024];
struct sockaddr_in serverAddr, clientAddr;
struct sockaddr_storage serverStorage;
socklen_t addr_size, client_addr_size;
int i;
/*Create UDP socket*/
udpSocket = socket(PF_INET, SOCK_DGRAM, 0);
/*Configure settings in address struct*/
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(20001);
serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);
/*Bind socket with address struct*/
bind(udpSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));
/*Initialize size variable to be used later on*/
addr_size = sizeof serverStorage;
while(1){
/* Try to receive any incoming UDP datagram. Address and port of
requesting client will be stored on serverStorage variable */
nBytes = recvfrom(udpSocket,buffer,1024,0,(struct sockaddr *)&serverStorage, &addr_size);
/*Convert message received to uppercase*/
for(i=0;i<nBytes-1;i++)
buffer[i] = toupper(buffer[i]);
/*Send uppercase message back to client, using serverStorage as the address*/
sendto(udpSocket,buffer,nBytes,0,(struct sockaddr *)&serverStorage,addr_size);
}
return 0;
}
I compiled and launched the udp server on my linux. 我在Linux上编译并启动了udp服务器。 and then I tried to see the listening UDP port with hetstat command but I did not see my server port listening:
然后我尝试使用hetstat命令查看侦听的UDP端口,但没有看到服务器侦听的端口:
sudo netstat -nulp | grep LISTEN
What I m missing? 我想念什么?
You may use the following command to specifically show the UDP bound ports: 您可以使用以下命令专门显示UDP绑定端口:
netstat -n --udp --listen
-n is for numerical representation of the ports, you may omit this -n用于端口的数字表示,您可以省略
--udp is to show only UDP protocol related information --udp仅显示UDP协议相关信息
--listen is to list only ports those have are bound to accept packets/connections --listen仅列出那些已经绑定接受数据包/连接的端口
The short command is: netstat -nul
简短的命令是:
netstat -nul
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