So I have a node server within a docker container. Right now I would like to have it communicate with the parent system's CUP server. However when I do an ajax call to the server, with port 631 exposed I get a 400 bad request error.
When looking at the CUPS logs it gives this reason for the rejection:
Request from "localhost" using invalid Host: field "host.docker.internal:631"
Now to even access the parent machine I have to use host.docker.internal to gain access, but I have not figured out a way to get cups to ignore the host or think its localhost.
Cups is watching for any serverAlias, and anything on port 631 so it "should" accept the call. Any ideas?
I had the same problem with CUPS (2.3.4) on osx. I spent several hours to fix the invalid Host: field error.
It seems that there's a bug, even when using SeverAlias * on cups conf.
For those who are looking for a workaround:
We have to change the Host header sent from the docker container to localhost in order to do so, I managed to set up an Nginx container listening on port 8888 and rewriting the Host field while proxy_pass to the host’s CUPS server.
This is the nginx conf.d:
server {
listen 8888;
location / {
proxy_pass http://host.docker.internal:631;
proxy_set_header Host localhost;
}}
Now instead of connecting to host.docker.internal:631 we connect the cups client to localhost:8888. (I have set up the nginx sever on the same docker container, you might want to set up a separate container depending on your needs)
Related
I recently installed Nextcloud over a lamp stack and want to run Traefik in front. For that, I tweaked the apache2 ports.conf to:
Listen: 127.0.0.1:180
. Now I also configured a .toml for Traefik that points to this address.
When I try to open the website, it gives me "Bad Gateway".
Trying to solve the error I searched the Traefik logs and found this:
msg="'502 Bad Gateway' caused by: dial tcp 127.0.0.1:180: connect: connection refused"
Thinking it must be a problem with trusted_proxies I configured Apache to open it's port to the public and also changed the Traefik .toml to see wheter it would work.
It did. That means that Nextcloud definetly accepts my proxy and the proxying works all good.
Problem is, It doesn't work when I configure it on localhost.
The access.log and nextcloud.log show nothing.
Any help?
Many thanks
The solution is simple, but hidden.
Traefik is a Docker container, so normally it can't communicate with services not in the docker network.
The fix is:
ip addr show docker0
Bind Apache2 to this IPv4: (my example) Listen 172.17.0.1:180 and also modify the Traefik Config.
Then Apache2 will listen on the docker0 network which containers have access to.
I'm working on a Linux VM on Azure which was set up by someone else (so I don't know all the details). I'm trying to connect it to a domain name.
The server has a "Hello World" program, so when I go to "example.com" I should be seeing "Hello World". Currently I'm just getting
Safari can't open the page "http://example.com" because Safari can't find the server "my domain.com"
I thought I'd start with making sure that the IP address connects to the server (which it did at one point. So I enter the IP address of the server (let's say it's "12.345.678.901") in the browser, and it can't connect... I get the error
Can't open the page "12.345.678.901" because the server where this page is located isn't responding
There's an Inbound port rule to allow connections for port 8080, so I tried "12.345.678.901:8080" but this time got
Can't open the page "12.345.678.901:8080" because Safari can't connect to the server
I don't know what to try next. Presumably something needs to be enabled on the server to allow the browser to connect?
The other inbound port rules are ssh on port 22 (TCP) and then what I assume are the standard Azure ones (I can't edit or delete them anyway).
To view your Linux VM inside the browser, you need to install a web server. Easiest to install and get working straight away is nginx.
First thing you need to do is SSH(port 22) into your VM using the username and IP address of the machine:
ssh username#ipaddress
Which will prompt you to enter a passphrase to gain access to the VM.
This also assumes your SSH public key exists inside ~/.ssh/authorized_keys on the VM. If you don't have this setup then you need to get the owner of the VM to copy your public key into this file. Otherwise you won't be able to connect and get a Permission denied (publickey) error.
Assuming the above works, you can install the nginx webserver with the following two commands:
sudo apt-get -y update
sudo apt-get -y install nginx
Then once this web server is installed, add an HTTP inbound port 80 rule inside the network settings. For security reasons, having your web server listen on this port is probably unsecure long term. Its just easier to get working when you choose this port to begin with, because its the default.
You can see what the default listening port by viewing the server configuration host file with cat /etc/nginx/sites-available/default:
#server {
# listen 80;
# listen [::]:80;
#
# server_name example.com;
#
# root /var/www/example.com;
# index index.html;
#
# location / {
# try_files $uri $uri/ =404;
# }
#}
Which shows the default port of 80. You can change this default port to 8080, then run sudo service nginx restart to restart the server and apply the changes. Additionally, you can have a look at this How to make Nginx Server Listen on Multiple Ports tutorial, which goes into more depth on how to configure listening ports for nginx webservers.
You should then be able to view your VM from a browser window(blurred out my IP address for security reasons):
You can also have a look at this Quickstart: Create a Linux virtual machine in the Azure portal tutorial for a step by step on how to get this setup in Azure.
You should first check to see if you have an entry for http://example.com. The reason could be that you do not have a DNS Entry and when you are trying to connect to it via the browser. Since you tried connecting to it via IP and it still did not work, I would suggest you check your Webserver configurations to make sure it is correctly listening for port 8080. Also, ensure that your webserver is also turned on as well. You can tail the webserver log and try to hit it via the IP like you did earlier and see if you see any errors in the logs. It would at least tell you if your request you are making on your browser is actually getting to the webserver.
I have installed nginx on my AMI by yum
sudo yum install nginx
And then, I open all port in my AMI security group
All traffic - All - All - 0.0.0.0/0
And then, I start nginx by command
sudo service nginx start
And then, I access my nginx web service by http://public-ip
but I cannot access by this way.
I try to check the connection in my server.
ssh my_account#my_ip
And then,
wget http://localhost -O-
And It worked fine.
I cannot figure out what is the root cause, and then I change nginx port from 80 to 8081 and I restart the nginx server.
And then, I try to access again. It worked fine. WTH...
http://public-ip:8081
I don't know exactly what is going on?
Could you tell me what is the problem.
I see a few possibilities:
You are blocking the connections with a firewall on the host.
Security Group rules disallow this access
You are in a VPC and have not set up an Internet Gateway or route to host
Your Nginx configurations are set to explicitly listen on host and port combinations such that it responds to "localhost" but not to the public IP or host name. You could post your Nginx configs and be more specific about how it doesn't work when you try remotely. It is timing out? Not resolving? Receiving an HTTP response but not what you expected?
I know that this is against the accepted convention but I need to run Nginx alongside a node.js server inside the same Docker container. I have no issues spinning up the container and getting Nginx and Node working alongside. Nginx works on Port 443 which is exposed by the container. The Node server listens on Port 8080 and is reverse proxied by Nginx
location /node/index.js {
proxy_pass http://127.0.0.1:8080;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X_Forwarded_For $proxy_add_x_forwarded_for;
}
Here is what I find
Access to the resources, https://example.com/text.txt on the Nginx server is straightforward
I startup the Nodejs server nodejs index.js & disown which has been configured to output a few diagnostic messages to a log file. Those messages tell me that the server is working just fine.
I can Telnet to Port 8080 from inside the Docker container - once again indicating that the Node server i sup and running
Precisely the same configuration but with Nginx running on a "real" server with Node running on the same server offers acceess to the Node server with no issues.
However, when I attempt to access the Node server running inside the Nginx Docker container, say, https://example.com/node/index.js I get a 404 error.
Examining my Nginx logs reveals that the request did reach Nginx inside its Docker host. However, examining the Node server log file indicates that the request never got forwarded.
It is not clear to me why this could be happening. From what I can tell when Nginx is running inside a Docker container it is failing to act as a reverse proxy for Node running inside the same container.
For good measure I tried EXPOSing the Node port, 8080 and starting up the Docker container with -p 8080:8080 -p 443:443 but that made no difference. I'd be most grateful to anyone who might be able to shed any light on what is going on here.
I am creating a test web app and have deployed it to AWS Ubuntu server using nginx..
I am getting a 502 Bad Gateway error when it tries to reach my API..
I am new to this and have started node.js and all seems to working fine except when I want to perform an API call to mongodb to read or write information. it is working fine locally so I am at a loss....
GET http://ec2-54-72-145-112.eu-west-1.compute.amazonaws.com/api/rest/golf 502 (Bad Gateway)
this is nginx server config
location /xxxxxxxxxxxxxxx{
alias /home/ubuntu/xxxxxxxxxxxxxx/site/public;
}
location /api/ {
proxy_pass http://127.0.x.1:8180/api/;
}
..
I know I may not be giving enough info but hopefully someone has an idea..
Thanks!
The nginx error message HTTP 502 indicates the nginx is working fine but cannot reach your specified proxy. So I'd suggest you to check whether the port and binding IP are correct.
You can check which ports are bound by which application using this command on your Ubuntu machine:
netstat -tulpen
You should see a line with the column "Local Address" and in your case the value 127.0.x.1:8180. If it's not there try to figure out which port is bound by your node application and reconfigure the nginx to use that port.