java.net.SocketException: Unrecognized Windows Sockets error: 0: JVM_Bind - javascript

I am getting this error when I am trying to run my project in eclipse:
Server started. Listening to the port 4444
java.net.SocketException: Unrecognized Windows Sockets error: 0: JVM_Bind
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:359)
at java.net.ServerSocket.bind(ServerSocket.java:319)
at java.net.ServerSocket.<init>(ServerSocket.java:185)
at java.net.ServerSocket.<init>(ServerSocket.java:97)
at MainServer.<init>(MainServer.java:30)
at MainServer.main(MainServer.java:86)
please suggest me some ways to clear this error.

It means that the target port number is already occupied by another application server.
First, You have to check any previous server application running in your eclipse if so, terminate them all.
then you will have a list what port is used or not by command if you are sure to find no server running :
netstat -an|grep port-number (*NIX)
or
netstat -an|findStr port-number (Windows).
For example in windows, you will see the port 47001 listening now.

Related

Node.js localhost:3000 refuses to connect

I am a total beginner of Node.js and I am unable to connect to localhost:3000
I use the following code in VS code, hit "node app.js" in terminal, and there is no error comes out in terminal at this point.
However, as I try to access the localhost:3000, it keeps refusing: "ERR_CONNECTION_REFUSED"
I searched on the internet for solutions and tried opening ports by creating an inbound rule on security settings, turned IIS on, used 127.0.0.1 instead, and still get refused. Does anyone have any idea how to solve this?
I am using Windows 10
const http = require('http');
var server = http.createServer(
(request, response)=>{
response.end('hello');
}
);
server.listen(3000);
Here is how to fix it. Your probably try to launch your server on a used port.
// enter this command in your terminal
lsof -i:3000
// this will output the related PID (process ID). Here: 1382.
node 1382 name 21u IPv6 blabla 0t0 TCP *:3000 (LISTEN)
// kill the PID in use
kill -9 1382
//relaunch your server
node app.js
I ran it on my computer and that code works fine. I would try other ports to see if they work.

live-server Error: listen EACCES 0.0.0.0:8080. even changing the ports not working? [duplicate]

I'm testing out an app (hopefully to run on heroku, but am having issues locally as well). It's giving me an EACCES error when it runs http.Server.listen() - but it only occurs on some ports.
So, locally I'm running:
joe#joebuntu:~$ node
> var h = require('http').createServer();
> h.listen(900);
Error: EACCES, Permission denied
at Server._doListen (net.js:1062:5)
at net.js:1033:14
at Object.lookup (dns.js:132:45)
at Server.listen (net.js:1027:20)
at [object Context]:1:3
at Interface.<anonymous> (repl.js:150:22)
at Interface.emit (events.js:42:17)
at Interface._onLine (readline.js:132:10)
at Interface._line (readline.js:387:8)
at Interface._ttyWrite (readline.js:564:14)
I don't have anything running on port 900 (or any of the other 20 ports I've tried), so this should work. The weird part is that it does work on some ports. For instance, port 3000 works perfectly.
What would cause this?
Update 1:
I figured out that on my local computer, the EACCES error is coming because I have to run node as root in order to bind to those certain ports. I don't know why this happens, but using sudo fixes it. However, this doesn't explain how I would fix it on Heroku. There is no way to run as root on Heroku, so how can I listen on port 80?
Running on your workstation
As a general rule, processes running without root privileges cannot bind to ports below 1024.
So try a higher port, or run with elevated privileges via sudo. You can downgrade privileges after you have bound to the low port using process.setgid and process.setuid.
Running on heroku
When running your apps on heroku you have to use the port as specified in the PORT environment variable.
See http://devcenter.heroku.com/articles/node-js
const server = require('http').createServer();
const port = process.env.PORT || 3000;
server.listen(port, () => console.log(`Listening on ${port}`));
#Windows
Another one reason - maybe your port has been excluded by some reasons.
So, try open CMD (command line) under admin rights and run :
net stop winnat
net start winnat
In my case it was enough.
Solution found here : https://medium.com/#Bartleby/ports-are-not-available-listen-tcp-0-0-0-0-3000-165892441b9d
Non-privileged user (not root) can't open a listening socket on ports below 1024.
Check this reference link:
Give Safe User Permission To Use Port 80
Remember, we do NOT want to run your applications as the root user,
but there is a hitch: your safe user does not have permission to use
the default HTTP port (80). You goal is to be able to publish a
website that visitors can use by navigating to an easy to use URL like
http://ip:port/
Unfortunately, unless you sign on as root, you’ll normally have to use
a URL like http://ip:port - where port number > 1024.
A lot of people get stuck here, but the solution is easy. There a few
options but this is the one I like. Type the following commands:
sudo apt-get install libcap2-bin
sudo setcap cap_net_bind_service=+ep `readlink -f \`which node\``
Now, when you tell a Node application that you want it to run on port
80, it will not complain.
On Windows System, restarting the service "Host Network Service", resolved the issue.
If you are using Windows. You should try restarting Windows NAT Driver service.
Open Command Prompt as Administrator and run
net stop winnat
then
net start winnat
That's it.
It's happening because I installed Nord VPN and it was auto staring with windows.
Another approach is to make port redirection:
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 900 -j REDIRECT --to-port 3000
And run your server on >1024 port:
require('http').createServer().listen(3000);
ps the same could be done for https(443) port by the way.
Spoiler alert: This answer may seems little funny.
I have spent more than 10 minutes to find out the root cause for this error in my system. I used this : PORT=2000; in my .env file.
Hope you already find it out. I had used a semicolon after declaring PORT number :'( I removed the extra sign and it started working.
I know this may not be answer for this question but hope it helps others who have faced same problem.
OMG!! In my case I was doing ....listen(ip, port) instead of ...listen(port, ip) and that was throwing up the error msg: Error: listen EACCES localhost
I was using port numbers >= 3000 and even tried with admin access. Nothing worked out. Then with a closer relook, I noticed the issue. Changed it to ...listen(port, ip) and everything started working fine!!
Just calling this out in case if its useful to someone else...
I had a similar problem that it was denying to run on port 8080, but also any other.
Turns out, it was because the env.local file it read contained comments after the variable names like:
PORT=8080 # The port the server runs at
And it interpreted it like that, trying to use port "8080 # The port the server runs at", which is obviously an invalid port (-1).
Removing the comments entirely solved it.
Using Windows 10 and Git Bash by the way.
I know it's not exactly the problem described here, but it might help someone out there. I landed on this question searching for the problem for my answer, so... maybe?
It means node is not able to listen on defined port. Change it to something like 1234 or 2000 or 3000 and restart your server.
restart was not enough! The only way to solve the problem is by the following:
You have to kill the service which run at that port.
at cmd, run as admin, then type :
netstat -aon | find /i "listening"
Then, you will get a list with the active service, search for the port that is running at 4200n and use the process id which is the last column to kill it by
: taskkill /F /PID 2652
I got this error on my mac because it ran the apache server by default using the same port as the one used by the node server which in my case was the port 80. All I had to do is stop it with sudo apachectl stop
Hope this helps someone.
Remember if you use sudo to bind to port 80 and are using the env variables PORT & NODE_ENV you must reexport those vars as you are now under root profile and not your user profile. So, to get this to work on my Mac i did the following:
sudo su
export NODE_ENV=production
export PORT=80
docpad run
I got this error on my mac too. I use npm run dev to run my Nodejs app in Windows and it works fine. But I got this error on my mac - error given was: Error: bind EACCES null:80.
One way to solve this is to run it with root access. You may use sudo npm run dev and will need you to put in your password.
It is generally preferable to serve your application on a non privileged port, such as 3000, which will work without root permissions.
reference: Node.js EACCES error when listening on http 80 port (permission denied)
this happens if the port you are trying to locally host on is portfowarded
Try authbind:
http://manpages.ubuntu.com/manpages/hardy/man1/authbind.1.html
After installing, you can add a file with the name of the port number you want to use in the following folder: /etc/authbind/byport/
Give it 500 permissions using chmod and change the ownership to the user you want to run the program under.
After that, do "authbind node ..." as that user in your project.
My error is resolved using (On Windows)
app.set('PORT', 4000 || process.env.PORT);
app.listen(app.get('PORT'), <IP4 address> , () => {
console.log("Server is running at " + app.get('PORT'));
});
Allow the NodeJS app to access the network in Windows Firewall.
My error got resolved just by changing port number in server.js
Specially in this line
const port = process.env.PORT || 8085;
I changed my port number to 8085 from 8080.
Hope it helps.
For me this issue affected all hosts and all ports on Windows in PowerShell.
Disabling Network Interfaces fixed the issue.
I had WiFi and an Ethernet connection and disabling the Ethernet Interface fixed this issue.
Open "Network Connections" to view your interfaces. Right-click and select "Disable".
This means the port is used somewhere else. so, you need to try another one or stop using the old port.
I tried every answer given above, but nothing works out, then I figured out that I forget to add const before declaring the variable in the .env file.
Before:
PORT = 5000;
HOST = "127.0.0.1";
After:
const PORT = 5000;
const HOST = "127.0.0.1";
So the possible reason for this would be related to typo in environment variables names or else not installed dotenv package .
So if there is any other error apart from typo and dotenv npm package ,then you must try these solutions which are given below:
First solution
for Windows only
Open cmd as run as administrator and then write two commands
net stop winnat
net start winnat
hope this may solve the problem ...
Second solution
for windows only
make sure to see that in your environment variable that there is no semicolon(;) at the end of the variable and there is no colon (:) after the variable name.
for example I was working on my project in which my env variables were not working so the structure for my .env file was like PORT:5000; CONNECTION_URL:MongoDbString.<password>/<dbname>; so it was giving me this error
Error: listen EACCES: permission denied 5000;
at Server.setupListenHandle [as _listen2] (node:net:1313:21)
at listenInCluster (node:net:1378:12)
at Server.listen (node:net:1476:5)
at Function.listen (E:\MERN REACT\mern_memories\server\node_modules\express\lib\application.js:618:24)
at file:///E:/MERN%20REACT/mern_memories/server/index.js:29:9
at processTicksAndRejections (node:internal/process/task_queues:96:5)
Emitted 'error' event on Server instance at:
at emitErrorNT (node:net:1357:8)
at processTicksAndRejections (node:internal/process/task_queues:83:21) {
code: 'EACCES',
errno: -4092,
syscall: 'listen',
address: '5000;',
port: -1
}
[nodemon] app crashed - waiting for file changes before starting...
So i did some changes in my env file this time i removed the colon(:) and replaced it with equal(=) and removed semi colon at the end so my .env file was looking like this
PORT = 5000
CONNECTION_URL = MongoDbString.<password>/<dbname>
After changing these thing my server was running on the port 5000 without any warning and issues
Hope this may works...
#code #developers #mernstack #nodejs #react #windows #hostservicenetwork #http #permission-denied #EACCES:-4092
After trying many different ways, re-installing IIS on my windows solved the problem.
The same issue happened to me.
You need to check out your server.js file where you are setting your listening port. Change port number wisely in all places, and it will solve your issue hopefully.
For me, it was just an error in the .env file. I deleted the comma at the end of each line and it was solved.
Before:
HOST=127.0.0.1,
After:
HOST=127.0.0.1
Error: listen EACCES: permission denied 3000;
i add "PORT = 3000;" while "PORT = 3000" .
just semicolon";" give error
remove semicolon and project run successfully
I had a similar problem that it was denying to run on port 5000,
Turns out, it was because the env.local file contained comma(';') after variable names like:
PORT= 5000;
And it interpreted it like that, trying to use port "5000;", which is obviously an invalid port (-1). Removing the ';' entirely solved it.
I know it's not exactly the problem described here, but it might help someone out there. I landed on this question searching for the problem for my answer, so... maybe?
This worked perfectly fine for me, set your port at the bottom of the page with this code instead
let port = process.env.PORT;
if (port == null || port == "") {
port = 3000;
}
app.listen(port, function() {
console.log('app started successfully')
});
Some times it is because of bad configuration the dot.env like: require("dotenv").config without () in your app middle ware or may be you write your port number with wrong syntax like instead of = you write : or add some other symbols in port number.

Running node app forever with sudo leads to errors [duplicate]

I'm testing out an app (hopefully to run on heroku, but am having issues locally as well). It's giving me an EACCES error when it runs http.Server.listen() - but it only occurs on some ports.
So, locally I'm running:
joe#joebuntu:~$ node
> var h = require('http').createServer();
> h.listen(900);
Error: EACCES, Permission denied
at Server._doListen (net.js:1062:5)
at net.js:1033:14
at Object.lookup (dns.js:132:45)
at Server.listen (net.js:1027:20)
at [object Context]:1:3
at Interface.<anonymous> (repl.js:150:22)
at Interface.emit (events.js:42:17)
at Interface._onLine (readline.js:132:10)
at Interface._line (readline.js:387:8)
at Interface._ttyWrite (readline.js:564:14)
I don't have anything running on port 900 (or any of the other 20 ports I've tried), so this should work. The weird part is that it does work on some ports. For instance, port 3000 works perfectly.
What would cause this?
Update 1:
I figured out that on my local computer, the EACCES error is coming because I have to run node as root in order to bind to those certain ports. I don't know why this happens, but using sudo fixes it. However, this doesn't explain how I would fix it on Heroku. There is no way to run as root on Heroku, so how can I listen on port 80?
Running on your workstation
As a general rule, processes running without root privileges cannot bind to ports below 1024.
So try a higher port, or run with elevated privileges via sudo. You can downgrade privileges after you have bound to the low port using process.setgid and process.setuid.
Running on heroku
When running your apps on heroku you have to use the port as specified in the PORT environment variable.
See http://devcenter.heroku.com/articles/node-js
const server = require('http').createServer();
const port = process.env.PORT || 3000;
server.listen(port, () => console.log(`Listening on ${port}`));
#Windows
Another one reason - maybe your port has been excluded by some reasons.
So, try open CMD (command line) under admin rights and run :
net stop winnat
net start winnat
In my case it was enough.
Solution found here : https://medium.com/#Bartleby/ports-are-not-available-listen-tcp-0-0-0-0-3000-165892441b9d
Non-privileged user (not root) can't open a listening socket on ports below 1024.
Check this reference link:
Give Safe User Permission To Use Port 80
Remember, we do NOT want to run your applications as the root user,
but there is a hitch: your safe user does not have permission to use
the default HTTP port (80). You goal is to be able to publish a
website that visitors can use by navigating to an easy to use URL like
http://ip:port/
Unfortunately, unless you sign on as root, you’ll normally have to use
a URL like http://ip:port - where port number > 1024.
A lot of people get stuck here, but the solution is easy. There a few
options but this is the one I like. Type the following commands:
sudo apt-get install libcap2-bin
sudo setcap cap_net_bind_service=+ep `readlink -f \`which node\``
Now, when you tell a Node application that you want it to run on port
80, it will not complain.
On Windows System, restarting the service "Host Network Service", resolved the issue.
If you are using Windows. You should try restarting Windows NAT Driver service.
Open Command Prompt as Administrator and run
net stop winnat
then
net start winnat
That's it.
It's happening because I installed Nord VPN and it was auto staring with windows.
Another approach is to make port redirection:
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 900 -j REDIRECT --to-port 3000
And run your server on >1024 port:
require('http').createServer().listen(3000);
ps the same could be done for https(443) port by the way.
Spoiler alert: This answer may seems little funny.
I have spent more than 10 minutes to find out the root cause for this error in my system. I used this : PORT=2000; in my .env file.
Hope you already find it out. I had used a semicolon after declaring PORT number :'( I removed the extra sign and it started working.
I know this may not be answer for this question but hope it helps others who have faced same problem.
OMG!! In my case I was doing ....listen(ip, port) instead of ...listen(port, ip) and that was throwing up the error msg: Error: listen EACCES localhost
I was using port numbers >= 3000 and even tried with admin access. Nothing worked out. Then with a closer relook, I noticed the issue. Changed it to ...listen(port, ip) and everything started working fine!!
Just calling this out in case if its useful to someone else...
I had a similar problem that it was denying to run on port 8080, but also any other.
Turns out, it was because the env.local file it read contained comments after the variable names like:
PORT=8080 # The port the server runs at
And it interpreted it like that, trying to use port "8080 # The port the server runs at", which is obviously an invalid port (-1).
Removing the comments entirely solved it.
Using Windows 10 and Git Bash by the way.
I know it's not exactly the problem described here, but it might help someone out there. I landed on this question searching for the problem for my answer, so... maybe?
It means node is not able to listen on defined port. Change it to something like 1234 or 2000 or 3000 and restart your server.
restart was not enough! The only way to solve the problem is by the following:
You have to kill the service which run at that port.
at cmd, run as admin, then type :
netstat -aon | find /i "listening"
Then, you will get a list with the active service, search for the port that is running at 4200n and use the process id which is the last column to kill it by
: taskkill /F /PID 2652
I got this error on my mac because it ran the apache server by default using the same port as the one used by the node server which in my case was the port 80. All I had to do is stop it with sudo apachectl stop
Hope this helps someone.
Remember if you use sudo to bind to port 80 and are using the env variables PORT & NODE_ENV you must reexport those vars as you are now under root profile and not your user profile. So, to get this to work on my Mac i did the following:
sudo su
export NODE_ENV=production
export PORT=80
docpad run
I got this error on my mac too. I use npm run dev to run my Nodejs app in Windows and it works fine. But I got this error on my mac - error given was: Error: bind EACCES null:80.
One way to solve this is to run it with root access. You may use sudo npm run dev and will need you to put in your password.
It is generally preferable to serve your application on a non privileged port, such as 3000, which will work without root permissions.
reference: Node.js EACCES error when listening on http 80 port (permission denied)
this happens if the port you are trying to locally host on is portfowarded
Try authbind:
http://manpages.ubuntu.com/manpages/hardy/man1/authbind.1.html
After installing, you can add a file with the name of the port number you want to use in the following folder: /etc/authbind/byport/
Give it 500 permissions using chmod and change the ownership to the user you want to run the program under.
After that, do "authbind node ..." as that user in your project.
My error is resolved using (On Windows)
app.set('PORT', 4000 || process.env.PORT);
app.listen(app.get('PORT'), <IP4 address> , () => {
console.log("Server is running at " + app.get('PORT'));
});
Allow the NodeJS app to access the network in Windows Firewall.
My error got resolved just by changing port number in server.js
Specially in this line
const port = process.env.PORT || 8085;
I changed my port number to 8085 from 8080.
Hope it helps.
For me this issue affected all hosts and all ports on Windows in PowerShell.
Disabling Network Interfaces fixed the issue.
I had WiFi and an Ethernet connection and disabling the Ethernet Interface fixed this issue.
Open "Network Connections" to view your interfaces. Right-click and select "Disable".
This means the port is used somewhere else. so, you need to try another one or stop using the old port.
I tried every answer given above, but nothing works out, then I figured out that I forget to add const before declaring the variable in the .env file.
Before:
PORT = 5000;
HOST = "127.0.0.1";
After:
const PORT = 5000;
const HOST = "127.0.0.1";
So the possible reason for this would be related to typo in environment variables names or else not installed dotenv package .
So if there is any other error apart from typo and dotenv npm package ,then you must try these solutions which are given below:
First solution
for Windows only
Open cmd as run as administrator and then write two commands
net stop winnat
net start winnat
hope this may solve the problem ...
Second solution
for windows only
make sure to see that in your environment variable that there is no semicolon(;) at the end of the variable and there is no colon (:) after the variable name.
for example I was working on my project in which my env variables were not working so the structure for my .env file was like PORT:5000; CONNECTION_URL:MongoDbString.<password>/<dbname>; so it was giving me this error
Error: listen EACCES: permission denied 5000;
at Server.setupListenHandle [as _listen2] (node:net:1313:21)
at listenInCluster (node:net:1378:12)
at Server.listen (node:net:1476:5)
at Function.listen (E:\MERN REACT\mern_memories\server\node_modules\express\lib\application.js:618:24)
at file:///E:/MERN%20REACT/mern_memories/server/index.js:29:9
at processTicksAndRejections (node:internal/process/task_queues:96:5)
Emitted 'error' event on Server instance at:
at emitErrorNT (node:net:1357:8)
at processTicksAndRejections (node:internal/process/task_queues:83:21) {
code: 'EACCES',
errno: -4092,
syscall: 'listen',
address: '5000;',
port: -1
}
[nodemon] app crashed - waiting for file changes before starting...
So i did some changes in my env file this time i removed the colon(:) and replaced it with equal(=) and removed semi colon at the end so my .env file was looking like this
PORT = 5000
CONNECTION_URL = MongoDbString.<password>/<dbname>
After changing these thing my server was running on the port 5000 without any warning and issues
Hope this may works...
#code #developers #mernstack #nodejs #react #windows #hostservicenetwork #http #permission-denied #EACCES:-4092
After trying many different ways, re-installing IIS on my windows solved the problem.
The same issue happened to me.
You need to check out your server.js file where you are setting your listening port. Change port number wisely in all places, and it will solve your issue hopefully.
For me, it was just an error in the .env file. I deleted the comma at the end of each line and it was solved.
Before:
HOST=127.0.0.1,
After:
HOST=127.0.0.1
Error: listen EACCES: permission denied 3000;
i add "PORT = 3000;" while "PORT = 3000" .
just semicolon";" give error
remove semicolon and project run successfully
I had a similar problem that it was denying to run on port 5000,
Turns out, it was because the env.local file contained comma(';') after variable names like:
PORT= 5000;
And it interpreted it like that, trying to use port "5000;", which is obviously an invalid port (-1). Removing the ';' entirely solved it.
I know it's not exactly the problem described here, but it might help someone out there. I landed on this question searching for the problem for my answer, so... maybe?
This worked perfectly fine for me, set your port at the bottom of the page with this code instead
let port = process.env.PORT;
if (port == null || port == "") {
port = 3000;
}
app.listen(port, function() {
console.log('app started successfully')
});
Some times it is because of bad configuration the dot.env like: require("dotenv").config without () in your app middle ware or may be you write your port number with wrong syntax like instead of = you write : or add some other symbols in port number.

Meteor deployed on server, but browser says site can't be reached

So I've deployed my meteor app, and have it up and running on an instance.
I've used the following environment variables:
MONGO_URL='mongodb://localhost:27017/meteor'
ROOT_URL='http://<my static ip>'
PORT=3000
And I run the program using the following command:
node bundle/main.js
It prints my "Meteor is starting up" that is printed using the console.log command, and then doesn't error out, but when I navigate to http://< my static ip >:3000 in a browser, I get an ERR_CONNECTION_REFUSED result.
My open mongod terminal says it's connecting fine to the MongoDB database.
Does anyone have any ideas on how to start debugging this issue?
Thanks.
In server you don't need to run meteor application on port 3000. You can run it on port 80 if the port is not being used by any other program.
If you are using port 80 make sure port 80 is opened by the network security rules.
If you are using port 3000 or any other port you will have to make sure that port is opened by the network security rules as above. Additionally you will have to mention the IP in your url, like http://<your_ip>:<port>

Unable to deploy Node app to Openshift

I'm trying to deploy a simple ExpressJS app I have to Openshift using the command line tools. I've provided a debug trace below:
>npm info ok
Preparing build for deployment
Deployment id is 5e2abc99
Activating deployment
HAProxy already running
HAProxy instance is started
Starting NodeJS cartridge
Sat Aug 15 2015 15:17:47 GMT-0400 (EDT): Starting application 'xxxxx' ...
Waiting for application port (8080) become available ...
Application 'xxxxx' failed to start (port 8080 not available)
and
Git Post-Receive Result: failure
Activation status: failure
Activation failed for the following gears:
55cf8fc589f5cf9dbf00023c (Error activating gear: CLIENT_ERROR: Failed to execute: 'control start' for /var/lib/openshift/55cf8fc589f5cf9dbf00023c/nodejs
#<IO:0x00000001ec7290>
#<IO:0x00000001ec7218>
>)
Deployment completed with status: failure
postreceive failed
However my app is listening on port 8080:
app.listen(process.env.OPENSHIFT_NODEJS_PORT || 8080);
Can anyone help?
Deploying an empty application doesn't seem to throw any errors.
Have you checked the log on the server? I was encountering a similar issue and it was because I had syntax errors in my script. If you SSH into your application and
tail app-root/logs/nodejs.log
you can see the console output for the app. Use -n [# of lines] to view more of the log if 10 isn't enough or use less and press shift + g to view the document starting at the bottom if you want to scroll up and down through it all.
Try to login via ssh to your openshift node. I use the rhc tool. Run your code and you will see where the problem is.

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