I'm using Windows 10 and Visual Studio 2016. I can't bind to port 80. I can bind to all other ports. The error printed is: "Bind of IP address 0.0.0.0 returned an error, port 80: No error"
Here is my code:
/* bind this socket to the server's Internet address */
if( bind(fd,(struct sockaddr *)server_addr,sizeof(struct sockaddr_in))<0 )
{
printf("Bind of IP address %s returned an error, port %d: %s\n",
inet_ntoa(server_addr->sin_addr), ntohs(server_addr->sin_port),
strerror(errno));
//close(fd);
return -1;
}
Use "netstat -o -q -a -n". Then use task manager and look at the Details tab. Click to sort the PID as low to high. Find the PID and notice the name of the program that has the port open. In my case System is listening on port 80 and since you can't kill System then you basically can't bind to port 80.
Well, you can use netstat to see if anyone else is listening, see this article:
https://technet.microsoft.com/en-us/library/bb490947.aspx
Find which process is already using port 80 and stop it.
You also need to be an admin or explicitly grant access to the user you're running as if you're binding port < 1024. See here
HttpListener Access Denied
Related
I have my server running under docker and start it with the command serve(app, listen='*:5000').
I can:
access it in container under both 127.0.0.1:5000 amd localhost:5000
access it from outside the container under localhost:5000
I cannot:
access it from outside container under '127.0.0.1:5000'
access it from local network using local ip (and this is what matters the most to me)
I was trying to pass the local address into the serve command but it throws error saying that the address cannot be accessed. Also tried the host='0.0.0.0'. Did not help.
Would anyone know how to make it visible outside of my machine?
ok so i found a solutions that seems to do the trick. the problem was wsl.
at github wsl repo there is a script that sets a bridge.
below i post the code so it does not perish.
credit to edwindijas
$found = $remoteport -match '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}';
if( $found ){
$remoteport = $matches[0];
} else{
echo "The Script Exited, the ip address of WSL 2 cannot be found";
exit;
}
#[Ports]
#All the ports you want to forward separated by coma
$ports=#(80,443,10000,3000,5000);
#[Static ip]
#You can change the addr to your ip config to listen to a specific address
$addr='0.0.0.0';
$ports_a = $ports -join ",";
#Remove Firewall Exception Rules
iex "Remove-NetFireWallRule -DisplayName 'WSL 2 Firewall Unlock' ";
#adding Exception Rules for inbound and outbound Rules
iex "New-NetFireWallRule -DisplayName 'WSL 2 Firewall Unlock' -Direction Outbound -LocalPort $ports_a -Action Allow -Protocol TCP";
iex "New-NetFireWallRule -DisplayName 'WSL 2 Firewall Unlock' -Direction Inbound -LocalPort $ports_a -Action Allow -Protocol TCP";
for( $i = 0; $i -lt $ports.length; $i++ ){
$port = $ports[$i];
iex "netsh interface portproxy delete v4tov4 listenport=$port listenaddress=$addr";
iex "netsh interface portproxy add v4tov4 listenport=$port listenaddress=$addr connectport=$port connectaddress=$remoteport";
}
If you have not already done so, try exposing port 5000.
This can be done by adding
EXPOSE 5000
to your Dockerfile. You will also need to have host='0.0.0.0' in your serve in order to be able to access your page from the local network.
Getting this in log while deploying image in openshift:
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.13. Set the 'ServerName' directive globally to suppress this message
(13)Permission denied: AH00072: make_sock: could not bind to address [::]:80
(13)Permission denied: AH00072: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
AH00015: Unable to open logs
Dockerfile:
FROM httpd:2.4
RUN echo "hello app" > /usr/local/apache2/htdocs/hello.html
also getting the error if i use EXPOSE 80
Ports up to 1024 are so called privileged ports this means that in order to bind to them, the user has to have root capabilities.
In your case, you are trying have your service listen on port 80, which is in that privileged port range.
By default openshift is not running any containers inside the Pods as root.
You will either have to adjust the user as which it runs or have it listen on a different port.
I'm trying to open port TCP 28016 and UDP 28015 for a game server in my compute engine VM running on Microsoft Windows Server 2016.
I've tried opening the opening inside my server using RDP, going to Windows Firewall setting and creating new inbound rules for both TCP 28016 and UDP 28015.
Also done setting firewall rules on my Cloud Platform Firewall Rules for both port.
When running my game server application, running netstat didn't show any of the port being used / not listening . Not even shows up. What did i do wrong ?
Edit : it now shows up on netstat -a -b , but didn't have LISTENING
If it doesn't show as LISTENING, it's not a firewall or "port forwarding" issue; rather, the application either isn't running, or is running but isn't configured to listen for connections on that port.
When I publish and subscribe at localhost its work fine.
When I try from my PC at home I just can't connect to the broker.
open TCP port in/out at security group - 1883 8883 8080
open the ports also at my ec2 instance firewall...
what is the problem? I use the public DNS by amazon as I think I should...
This is an exercise at diagnosing network problems:
1) netstat -a -n | grep 1883
will tell you whether your broker is configured correctly
2) wireshark packet capture will tell you whether your system is receiving packets at the specific port
You will not get an answer until you at least do those.
How I can say a port is open or closed. What's the exact meaning of Open port and closed port.
My favorite tool to check if a specific port is open or closed is telnet. You'll find this tool on all of the operating systems.
The syntax is: telnet <hostname/ip> <port>
This is what it looks like if the port is open:
telnet localhost 3306
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
This is what it looks like if the port is closed:
telnet localhost 9999
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
telnet: Unable to connect to remote host
Based on your use case, you may need to do this from a different machine, just to rule out firewall rules being an issue. For example, just because I am able to telnet to port 3306 locally doesn't mean that other machines are able to access port 3306. They may see it as closed due to firewall rules.
As far as what open/closed ports means, an open port allows data to be sent to a program listening on that port. In the examples above, port 3306 is open. MySQL server is listening on that port. That allows MySQL clients to connect to the MySQL database and issue queries and so on.
There are other tools to check the status of multiple ports. You can Google for Port Scanner along with the OS you are using for additional options.
A port that's opened is a port to which you can connect (TCP)/ send data (UDP). It is open because a process opened it.
There are many different types of ports. These used on the Internet are TCP and UDP ports.
To see the list of existing connections you can use netstat (available under Unix and MS-Windows). Under Linux, we have the -l (--listen) command line option to limit the list to opened ports (i.e. listening ports).
> netstat -n64l
...
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN
...
udp 0 0 0.0.0.0:53 0.0.0.0:*
...
raw 0 0 0.0.0.0:1 0.0.0.0:* 7
...
In my example, I show a TCP port 6000 opened. This is generally for X11 access (so you can open windows between computers.)
The other port, 53, is a UDP port used by the DNS system. Notice that UDP port are "just opened". You can always send packets to them. You cannot create a client/server connection like you do with TCP/IP. Hence, in this case you do not see the LISTEN state.
The last entry here is "raw". This is a local type of port which only works between processes within one computer. It may be used by processes to send RPC events and such.
Update:
Since then netstat has been somewhat deprecated and you may want to learn about ss instead:
ss -l4n
-- or --
ss -l6n
Unfortunately, at the moment you have to select either -4 or -6 for the corresponding stack (IPv4 or IPv6).
If you're interested in writing C/C++ code or alike, you can read that information from /proc/net/.... For example, the TCP connections are found here:
/proc/net/tcp (IPv4)
/proc/net/tcp6 (IPv6)
Similarly, you'll see UDP files and a Unix file.
Programmatically, if you are only checking one port then you can just attempt a connection. If the port is open, then it will connect. You can then close the connection immediately.
Finally, there is the Kernel direct socket connection for socket diagnostics like so:
int s = socket(
AF_NETLINK
, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK
, NETLINK_SOCK_DIAG);
The main problem I have with that one is that it does not really send you events when something changes. But you can read the current state in structures which is safer than attempting to parse files in /proc/....
I have some code handling such a socket in my eventdispatcher library. Only it still has to do a poll to get the data since the kernel does not generate events on its own (i.e. a push is much better since it only has to happen once when an event actually happens).