i'm facing difficulties to hit the api runs on ubuntu inside virtualbox. virtualbox's ip address is 10.0.2.15 . when im trying to hit this ip, i cant access it.
so help me to hit the rails api, that runs on port 3000
TIA
Probably your Linux firewall is blocking connection.
So you can do two things make changes in IPtables rule to allow connection
OR
Just turn IPtables service off
Related
I have a DDev project in WSL2. Whenever I try to start it I get an error:
Error response from daemon: Ports are not available: exposing port TCP 127.0.0.1:443 -> 0.0.0.0:0: listen tcp 127.0.0.1:443: bind: Only one usage of each socket address (protocol/network address/port) is normally permitted.'
Sometimes it's also port 80. But most importantly before starting the project none of those ports is occupied. Neither inside WSL nor on the Windows Host. I am also able to start another docker container exposing on those ports. I am even to manually start the router with
COMPOSE_PROJECT_NAME=ddev-project docker-compose -f /home/crs/.ddev/.router-compose-full.yaml -p ddev-router up -d
but I still can't access the project even though the router seems to be running.
ddev debug test also fails.
I tried updating and reinstalling both Docker Desktop and ddev.
I also tried changing the router_http_port and router_https_port to something else. Then it does seem to start the project but I still can't access anything through the ddev router.
The web containers seem to work fine, when not going through the router I can access the project.
Debugging for this is explained in the docs, but it's slightly trickier on WSL2, because the process that's giving trouble may be either on the Windows side or the WSL2 side.
As explained there, you can either find the competing process or change to use different ports in DDEV.
On WSL2, port 80 is often apache2, which some distros have by default, so you can stop it or uninstall it without any harm. Port 443 is something occupied by random poorly behaved processes on Windows, including sometimes virus checkers.
If you use the techniques there to check for competing ports you'll almost certainly solve this.
Another technique is to use curl localhost, curl -I localhost or curl https://localhost and curl -I https://localhost to see if the HTTP response gives you a clue what process is problematic.
Also note that sometimes Docker Desktop is poorly behaved if you're using it, and you may have to restart it.
But if changing the ports to, say, 8080 and 8443 didn't solve it for you then you have a connectivity problem, likely a firewall. That's a completely different problem and you'll want to walk through the troubleshooting instructions in docs and start with temporarily turning off firewall and VPN.
For more interactive help, join us in the DDEV Discord.
I'm learning Docker networking. I'm using Docker Desktop on Windows.
I'm trying to understand the following observations:
Short version in a picture:
Longer version:
First setup (data from container to host)
I have a simple app running in a container. It sends one UDP-datagram to a specific port on the host (using "host.docker.internal")
I have a corresponding app running on the host. It listens to the port and is supposed to receive the UDP-datagram.
That works without publishing any ports in docker (expected behavior!).
Second setup (data from host to container)
I have a simple app on the host. It sends one UDP-datagram to a specific port on the loopback network (using "localhost")
I have a corresponding app running in a container. It listens to the port and is supposed to receives the UDP-datagram.
That works only if the container is run with option -p port:port/udp (expected behavior!).
Third setup (combination of the other two)
I have an app "Requestor" running in a container. It sends a UDP request-message to a specific port on the host and then wants to receive a response-message.
I have a corresponding app "Responder" running on the host. It listens to the port and is supposed to receive the request-message. Then it sends a UDP response-message to the endpoint of the request-message.
This works as well, and - that's what I don't understand - without publishing the port for the response-message!
How does this work? I'm pretty sure there's some basic networking-knowledge that I simply don't have already to explain this. I would be pleased to learn some background on this.
Sidenote:
Since I can do curl www.google.com successfully from inside a container, I realize that a container definitely must not publish ports to receive any data. But there's TCP involved here to establish a connection. UDP on the other hand is "connectionless", so that can't be the (whole) explanation.
After further investigation, NAT seems to be the answer.
According to these explanations, a NAT is involved between the loopback interface and the docker0 bridge.
This is less recognizable with Docker Desktop for Windows because of the following (source):
Because of the way networking is implemented in Docker Desktop for Windows, you cannot see a docker0 interface on the host. This interface is actually within the virtual machine.
So I've been trying to host my own Minecraft server for a while now and I hit a snag.
I have proxmox (192.168.2.100) running an ubuntnu server VM (192.168.2.101) which has a docker container running my Minecraft server. I can connect to the server locally just fine using the ubuntu's IP address and minecraft port, but when I try to port forward the server, I can't connect to it. I checked to see if my port was exposed or not and it is so I know it's not that.
This is the container that I'm using
Okay, so after a long time looking at configurations and some help from the proxmox forum, it turns out that my modem doesn't support NAT reflection which means that any attempts to access my server though my public IP on the same network wouldn't work at all. I used my phone's mobile network to test if I could access the server from outside my local network and it worked just fine!
I have been running a media cluster for sometime without any issues. I have everything networked into two different docker networks... the first network just bridges the docker instance to the local machine, the second network is a docker VPN container that I use for the other media services (an earlier version of what I am working on can be found here: https://github.com/Xander-Rudolph/MediaDocker)
The strangest thing happened today though. I ran the docker update for windows and now docker spools up without any errors or issues, however none of the services work outside of the machine running docker. Usually I have a poke through for a couple of the services in my router (namely wordpress/joomla which is on the bridge) and they work outside of my local network, but none of them are working anymore. I was able to confirm its not the DNS A record because I'm able to use the RDP ports I have mapped for my router, and when I test on another machine in the same network, it can't access the services via the internal IP (but it can RDP).
Anyone have any idea what could have changed to break this? I've already updated all my docker images and even rebuilt my VPN container (before I realized its a networking issue). What are some steps I can do to try to troubleshoot what is going wrong in docker to prevent access outside of localhost?
Update
I've been able to rule out the docker update as the root cause... I upgraded docker on my laptop (which was previously running the same version as my desktop) and its not having the same issue... this configuration must be localized to this desktop... No idea what the issue is... Will try a linux VM on the desktop instead of docker for windows...
Update 2
After a lot of screwing around in both a VM and in WSL, I'm still only able to access the docker services from localhost but not a different machine on my network or via the IP on the host machine (perhaps something similar to this: Can't access localhost via IP address). RDP does work so the computer is accessible but the services are not.
I'm not sure if this is a result of a docker networking config or a windows network config (I'm using WSL with docker installed on ubuntu 20.08) but I'm not seeing anything stick out. I'm going to remove the tag for docker windows but this is definitely an issue with networking and I suspect it has something to do with the fact that the containers are running behind a VPN... although I don't know why I would be able to access them on localhost but not the IP on another VM...
When I run
netstat -a -o
on WSL I can see the established ports on localhost... EX:
tcp 0 0 localhost:7878 localhost:37520 ESTABLISHED
but when I look on the host machine (for wsl) I don't see the connection. I tried to use netsh to create a firewall rule to see if that would help:
netsh advfirewall firewall add rule name="TCP Port 7878" dir=in localport=7878 protocol=TCP action=allow
but it didn't have any effect.
Any suggestions for ways to trace the network to see where/how its failing/getting blocked would be extremely helpful.
Your question: "...What are some steps I can do to try to troubleshoot what is going wrong in docker to prevent access outside of localhost?..."
Troubleshooting help for you, first do you have multiple networking adapters (Ethernet, Wi-Fi, etc.) present on the host. First ensure, the priority of these adapters needs to be configured in correct order so the Windows networking stack can correctly choose gateway routes.
Now, to fix this set your primary internet-connected networking adapter to have the lowest InterfaceMetric value, use can use these Powershell commands from an elevated console:
Get-NetIPInterface -AddressFamily IPv4 | Sort-Object -Property InterfaceMetric -Descending
Please ensure that the host's primary internet-connected network adapter has the lowest InterfaceMetric value.
// Use this command to make the change for e.g. lets say your
// primary adapter InterfaceAlias is 'Wi-Fi'
Set-NetIPInterface -InterfaceAlias 'Wi-Fi' -InterfaceMetric 3
Now step two, if your host's primary network adapter is bridged because you have an External virtual switch setup in Hyper-V, then you will set the external virtual switch to have the lowest InterfaceMetric value.
Lastly, confirm/verify your routing tables, when you run this, the last line should show the primary adapter's gateway address along with it's ifMetric value):
Get-NetRoute -AddressFamily IPv4
If you’re using Docker Toolbox then any port you publish with docker run -p will be published on the Toolbox VM’s private IP address.
docker-machine ip will tell you.
It is frequently
192.168.99.100
Taken from: https://forums.docker.com/t/cant-connect-to-container-on-localhost-with-port-mapping/52716/25
After several attempts using the references below, I was still not getting anywhere. The recommendation by #derple didn't get me anywhere (since I was in wsl) but the article he linked someone had said they switched to linux and uninstalled and reinstalled docker desktop... and for some stupid reason that works.
These are my exact steps I took to fix it:
Uninstall docker desktop
Install WSL and docker inside an ubuntu18.04 instance in wsl
Test docker in wsl with localhost (worked only on localhost still)
Uninstall WSL using windows add/remove features
reinstall docker desktop
Oddly the get-netipinterface and get-netroute look exactly the same as they did before I did the uninstall and reinstall but things seem to be working now... I have no idea why the above worked...
I am trying for nginx proxy manager (running in a docker container) to connect to another docker container that has port 8080 open on it. When I setup the proxy to connect to 192.168.0.29:8080 the ip address of the host, but it doesn't work, the browser just says that the site didn't send any data.
I tried setting up the reverse proxy with other services (that weren't running inside a docker container), and they worked flawlessly. So, I've concluded, the problem is something with the docker containers.
First, I tried replacing the ip address with the address of the container (shown in portainer) which showed to be 172.17.0.2. But, that didn't work. I can confirm that both containers are in the same network, bridge.
I could not find any solutions for this problem either here, at Stack Overflow, or anywhere else. Hope there's enough data to solve this problem. Thanks ahead of time!
Edit:
running arp -na from within the container gives this output:
[root#docker-00244f7ab2cc:/app]# arp -na
? (172.17.0.1) at 02:42:d1:fc:fc:6b [ether] on eth0
I found the solution to my question after lots of searching and testing and it's quite simple. The solution is to start the nginx proxy manager docker container on the host network instead of the bridge network. Then, you can use localhost and then the port to refer to which service you want to redirect to.