I have a node application listening on port 80, I have set the security groups open on port 80.
But, when I access my webapp in browser via public ip(http://xx.xxx.xx.xxx/), it doesn't show up.
What could be the issue?
I've use this doc as a guide https://aws.amazon.com/premiumsupport/knowledge-center/connect-http-https-ec2/
When your security group already allowed traffic It means something wrong with the instance.
The first step to debug such an issue to verify the application status inside the instance.
do ssh to the instance and verify is the instance responding on localhost curl localhost
check is the process running, if you are using any nodejs process manager like pm2 pm2 list or forever forever list or ps -aux | grep node
Verify is the server running on port 80.
check is the port occupied netstat -antu | grep LISTEN
In short, if the application responding on localhost using curl localhost, then as mentioned in the comment then the instance is in the private subnet.
you can check this article to know about public and private subnet.
So The answer was, my security groups were fine. My app wasn't running because I didn't set the environment variable correctly. sudo PORT=80 node server.js was the command I needed.
Related
I'm running a webpack-dev-server application inside a Docker container (node:4.2.1). If I try to connect to the server port from within the container - it works fine. However, trying to connect it from the host computer results in reset connection (the port is published, of course). How can I fix it?
This issue is not a docker problem.
Add --host=0.0.0.0 to your webpack command.
You need to connect to your page like this:
http://host:port/webpack-dev-server/index.html
Look to the iframe mode
You need to make sure:
you docker container has mapped the EXPOSE'd port to a host port
docker run -p x:y
your VM (if you are using docker machine with a VM) has forwarded that mapped port to the actual host (the host of the VM).
See "How to access tomcat running in docker container from browser?"
I am running a angular app on node server and in server.js I have specified app.listen(8084,localhost)..So when i run npm start in the docker container and try to -p 8084:8084 in docker run I was not able to get anything, even though the curl command inside my container curl localhost:8084 was giving me right result.
So i change the app.listen(8084) and the -p 8084:8084 started working..I am not sure why ?
When you open socket, you need to bind it to some interface in your system. There are predefined values:
0.0.0.0 - all interfaces, your service will be available from any interface
locahost, 127.0.0.1 - bind locally. That means service is NOT available from oustide -- this is your case.
You also can specify particular interface IP address to bind to it.
When you start your container, by default docker start default bridge network, so your container is being put into separate network and to access it, you need to allow incoming remote connections in container.
You bind your service to localhost into a container, so no communication is possible outside the container. localhost for your node server is not the same than localhost for your container.
I have an app set to listen to port 66.
First I tried to run it with sudo node myapp.js . I was able to access it at the correct url (ip:66). Then I stopped the app (Ctrl+c) and started it with pm2, sudo pm2 start app.js. The status is online. However, that same url is now inaccessible.
Running sudo pm2 logs while the app is started with pm2 gives me the error EACCESS for port 66. No one else is running the app, and I am sure I am only using one console and killing the node service before starting it with pm2.
Pm2 was installed globally. Server is Debian stretch. Nodejs version is 8.x
I am logging as a normal user and using sudo to run the app.
on linux systems normal users are not allowed to listen to ports below 1024. There are several ways around this.
You can change this rule to allow non root users to open such ports. But this is a security risc and is not recommended. So i won't add a link to this solution.
you can also listen to a port that is greater than 1024 and then use a forward rule in your firewall to route port 66 to the port you opened.
https://www.systutorials.com/816/port-forwarding-using-iptables/
my (and pm2's) prefered solution is to listen to a port greater than 1024 and use a reverse proxy like nginx to route apps running on that server.
http://pm2.keymetrics.io/docs/tutorials/pm2-nginx-production-setup
Im running my node app with grunt on a DO droplet. I start the server
Running "connect:server" (connect) task
Waiting forever...
Started connect web server on http://localhost:3000
But when I navigate to my dropletIP:3000 I cannot see the app, I get:
This site can’t be reached
mydropletIP refused to connect.
Shouldn't my app be available? I don't have nginx or anything installed.
I was having similar problem but the solution was simple. Change from 'localhost' to '0.0.0.0' i.e
.listen(8080, '0.0.0.0');
And then to test your api just enter your static ip of droplet with port that you have entered i.e droplet-ip:8080
Check the particular port is opened or not ,using following command
sudo ufw status
If any Firewall enabled and any port is block means you can see that.
netstat -an | grep "LISTEN " ( List of listening port on server)
I need this info ,then only we can find a problem
I have a VPS with node.js installed, I already uploaded a basic example to test it on the server, so I tried doing this:
I access by SSH, navigate to my project folder and run
node app.js
I get this message
Express server listening on port 8080
I thought i could see my app here
example.com:8080 or server.example:8080... but nothing. Then I tried with the info from os.networkInterfaces(); and os.host(); and still nothing happen
could you help me out? as you can see I am a total noob on node.js. What I'm doing wrong? or what should I do before running my app? Something related to DNS's? i have no idea
How do you ssh to your host? with ip or name? Is it something like:
ssh root#example.com
if so then at least you know your DNS is ok.
Once on the server do a
netstat -a
if you find *:8080 then your server is listening in the default ip. If you see something like 12.23.45.67:8080 then this number is the ip your server is listening.
ifconfig
will give you the servers ip. This should be the same as the ip of example.com. If not then maybe there is some router/firewall in front of your server and you have to configure that to allow port 8080 to reach your server.
if someone ever has the same problem this is how i solved on CentOS:
Open this file
/ Etc / csf / csf.conf
Add the required port
Allow incoming TCP ports
TCP_IN = "20,21,22,25,53,80,110,143,443,465,587,993,995,26"
Allow outgoing TCP ports
TCP_OUT = "20,21,22,25,37,43,53,80,110,113,443,587,873"
Restart
# # Csf-r