I can not open certain ports via firwall rules in Google Cloud Platform - debugging

les
I created the instance from boot image.
but always can not open port 7000 via firewall rules...and egress is (allow all), anybody knows where the problem is?
System: Debian 10
ssh in terminal and
sudo natstat -plnt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 458/sshd
tcp6 0 0 :::22 :::* LISTEN 458/sshd
Is there any way to turn the port 7000 on ?
Encoutered the same issue when tring to open other ports like 5678...etc.

First of all you need to set the GCP firewall rule as "ingress".
Ingress is needed to allow incoming connections to the instance.
Regarding the ports, it does not open or activate by itself or in automatic, you need to have a service listening on that port.
However there are some tools used which allows you to activate the port by some time for testing purposes.
You can use tools like iperf3 to activate the port.
Install iperf3 for your vm with the command below.
sudo apt-get install iperf3
Once you have installed iperf3 you need to run the command below. ("-s" indicates your instance is in "server" mode, the "-p" is to set the port you prefer)
iperf -s -p 7000
On your remote machine (Client) you also need to install iperf3, if it is also a linux machine you can try the same command I mentioned earlier.
Once you have installed iperf3 use the below comamnd to reach the VM pointing the port 7000. ("-c" indicates client mode,the "-p" is to set the port the server is listening).
iperf -c [server ip address] -p 7000
Please refer to iperf
Another useful tool is netcat

Related

Able to open TCP port but not listening

Using Add rule in windows firewall, I was able to open TCP port 15537. When i am trying to executing command netstat -ano on terminal windows, this port is not listed. I tried to execute telnet command on terminal window (e.g. telnet IP port) but getting
Connecting To localhost...Could not open connection to the host, on port 15537: Connect failed
Then I downloaded PortQry application and execute it from different machine, this machine is also in the same network, the result I received was
"Not Listening".
I already spent more than 2 days and asked internal group but could not find solution.
Note: both machines are having Windows 10 OS.
No solution is needed as no problem is indicated in the question. You have opened a TCP port successfully. You have not made any attempt to cause anything to listen to that TCP port.
It's not clear what results you expected, but you got the results that you should have expected. Nothing is wrong. The port is open because you opened it. Nothing is listening on that port because you didn't set anything to listen on that port.
There may be some forwarding rules? Since the purpose of access is not on the local machine, the netstat command cannot see the port on listening, but it can see the next action based on this port, usually to do some forwarding
I am not very familiar with windows firewall configuration, but I know that if there is a forwarding rule in linux, like
-p tcp -m tcp --dport 8080 -j {other forwading chain}
we can not see 8080 listening on this host (netstat -tunpl), but telnet host:8080 may see connected
Use nmap instead of netstat for detecting opening port
nmap -p your_port_number your_local_ip
Run service on that port
For eg- In my case,in order to open port,I use
"service ssh start" or "service apache2 start "and it's open port 22 and 80 for connection respectively in my linux machine.
On using nmap in my lan network both ports opened.
Hope it help

access host's ssh tunnel from docker container

Using ubuntu tusty, there is a service running on a remote machine, that I can access via port forwarding through an ssh tunnel from localhost:9999.
I have a docker container running. I need to access that remote service via the host's tunnel, from within the container.
I tried tunneling from the container to the host with -L 9000:host-ip:9999 , then accessing the service through 127.0.0.1:9000 from within the container fails to connect. To check wether the port mapping was on, I tried
nc -luv -p 9999 # at host
nc -luv -p 9000 # at container
following this, parag. 2 but there was no perceived communication, even when doing
nc -luv host-ip -p 9000
at the container
I also tried mapping the ports via docker run -p 9999:9000 , but this reports that the bind failed because the host port is already in use (from the host tunnel to the remote machine, presumably).
So my questions are
1 - How will I achieve the connection? Do I need to setup an ssh tunnel to the host, or can this be achieved with the docker port mapping alone?
2 - What's a quick way to test that the connection is up? Via bash, preferably.
Thanks.
Using your hosts network as network for your containers via --net=host or in docker-compose via network_mode: host is one option but this has the unwanted side effect that (a) you now expose the container ports in your host system and (b) that you cannot connect to those containers anymore that are not mapped to your host network.
In your case, a quick and cleaner solution would be to make your ssh tunnel "available" to your docker containers (e.g. by binding ssh to the docker0 bridge) instead of exposing your docker containers in your host environment (as suggested in the accepted answer).
Setting up the tunnel:
For this to work, retrieve the ip your docker0 bridge is using via:
ifconfig
you will see something like this:
docker0 Link encap:Ethernet HWaddr 03:41:4a:26:b7:31
inet addr:172.17.0.1 Bcast:172.17.255.255 Mask:255.255.0.0
Now you need to tell ssh to bind to this ip to listen for traffic directed towards port 9000 via
ssh -L 172.17.0.1:9000:host-ip:9999
Without setting the bind_address, :9000 would only be available to your host's loopback interface and not per se to your docker containers.
Side note: You could also bind your tunnel to 0.0.0.0, which will make ssh listen to all interfaces.
Setting up your application:
In your containerized application use the same docker0 ip to connect to the server: 172.17.0.1:9000. Now traffic being routed through your docker0 bridge will also reach your ssh tunnel :)
For example, if you have a "DOT.NET Core" application that needs to connect to a remote db located at :9000, your "ConnectionString" would contain "server=172.17.0.1,9000;.
Forwarding multiple connections:
When dealing with multiple outgoing connections (e.g. a docker container needs to connect to multiple remote DB's via tunnel), several valid techniques exist but an easy and straightforward way is to simply create multiple tunnels listening to traffic arriving at different docker0 bridge ports.
Within your ssh tunnel command (ssh -L [bind_address:]port:host:hostport] [user#]hostname), the port part of the bind_address does not have to match the hostport of the host and, therefore, can be freely chosen by you. So within your docker containers just channel the traffic to different ports of your docker0 bridge and then create several ssh tunnel commands (one for each port you are listening to) that intercept data at these ports and then forward it to the different hosts and hostports of your choice.
on MacOS (tested in v19.03.2),
1) create a tunnel on host
ssh -i key.pem username#jump_server -L 3336:mysql_host:3306 -N
2) from container, you can use host.docker.internal or docker.for.mac.localhost or docker.for.mac.host.internal to reference host.
example,
mysql -h host.docker.internal -P 3336 -u admin -p
note from docker-for-mac official doc
I WANT TO CONNECT FROM A CONTAINER TO A SERVICE ON THE HOST
The host has a changing IP address (or none if you have no network access).
From 18.03 onwards our recommendation is to connect to the special DNS
name host.docker.internal, which resolves to the internal IP address
used by the host. This is for development purpose and will not work in
a production environment outside of Docker Desktop for Mac.
The gateway is also reachable as gateway.docker.internal.
I think you can do it by adding --net=host to your docker run. But see also this question: Forward host port to docker container
I'd like to share my solution to this. My case was as follows: I had a PostgreSQL SSH tunnel on my host and I needed one of my containers from the stack to connect to a database through it.
I spent hours trying to find a solution (Ubuntu + Docker 19.03) and I failed. Instead of doing voodoo magic with iptables, doing modifications to the settings of the Docker engine itself I came up with a solution and was shocked I didn't thought of this earlier. The most important thing was I didn't want to use the host mode: security first.
Instead of trying to allow a container to talk to the host, I simply added another service to the stack, which would create the tunnel, so other containers could talk to easily without any hacks.
After configuring a host inside my ~/.ssh/config:
Host project-postgres-tunnel
HostName remote.server.host
User sshuser
Port 2200
ForwardAgent yes
TCPKeepAlive yes
ConnectTimeout 5
ServerAliveCountMax 10
ServerAliveInterval 15
And adding a service to the stack:
postgres:
image: cagataygurturk/docker-ssh-tunnel:0.0.1
volumes:
- $HOME/.ssh:/root/ssh:ro
environment:
TUNNEL_HOST: project-postgres-tunnel
REMOTE_HOST: localhost
LOCAL_PORT: 5432
REMOTE_PORT: 5432
# uncomment if you wish to access the tunnel on the host
#ports:
# - 5432:5432
The PHP container started talking through the tunnel without any problems:
postgresql://user:password#postgres/db?serverVersion=11&charset=utf8
Just remember to put your public key inside that host if you haven't already:
ssh-copy-id project-postgres-tunnel
I'm pretty sure this will work regardless of the OS used (MacOS / Linux).
I agree with #hlobit that #B12Toaster answer should be the accepted answer.
In case anyone hits this problem but with a slightly different setup with the SSH tunnel, here are my findings. In my case, instead of creating a tunnel from Docker host machine to remote machine using ssh -L, I was creating remote forward SSH tunnel from remote machine to Docker host machine using ssh -L.
In this setup, by default sshd does NOT allow gateway ports, i.e. in file /etc/ssh/sshd_config on Docker host, the GatewayPorts no should be uncommented and set to GatewayPorts yes or GatewayPorts clientspecified. I configured GatewayPorts clientspecified and configured the remote forward SSH tunnel by ssh -L 172.17.0.1:dockerHostPort:localhost:sshClientPort user#dockerHost. Remember to restart sshd after changing /etc/ssh/sshd_config (sudo systemctl restart sshd).
Your Docker container should be able to connect to Docker host on 172.17.0.1:dockerHostPort and this in turn gets tunnelled back to SSH client's localhost:sshClientPort.
References:
https://www.ssh.com/ssh/tunneling/example
https://docs.docker.com/network/network-tutorial-host/
https://docs.docker.com/network/host/
My 2 cents for Ubuntu 18.04 - a very simple answer, no need for extra tunnels, extra containers, extra docker options or exposing host.
Simply, when creating a reverse tunnel make sure ssh binds to all interfaces as, by default, it binds ports of the reverse tunnel to localhost only. For example, in putty make sure that option Connection->SSH->Tunnels Remote ports do the same (SSH-2 only) is ticked.
This is more or less equivalent to specifying the binding address 0.0.0.0 for the remote part of the tunnel (more details here):
-R [bind_address:]port:host:hostport
However, this did not work for me unless I allowed the GatewayPorts option in my sshd server configuration. Many thanks to Stefan Seidel for his great answer.
In short: (1) you bind the reverse tunnel to 0.0.0.0, (2) you let the sshd server to accept such tunnels.
Once this is done I can access my remote server from my docker containers via the docker gateway 172.17.0.1 and port bound to the host.
On my side, running Docker in Windows Subsystem for Linux (WSL v1), I couldn't use docker0 connection approach. host.docker.internal also doesn't resolve (latest docker version).
However, I found out I could directly use the host-ip insider my docker container.
Get your Host IP (Windows cmd: ipconfig), e.g. 192.168.0.5
Bash into your Container and test if you can ping your host ip:
- docker exec -it d6b4be5b20f7 /bin/bash
- apt-get update && apt-get install iputils-ping
- ping 192.168.0.5
PING 192.168.0.5 (192.168.0.5) 56(84) bytes of data.
64 bytes from 192.168.0.5 : icmp_seq=1 ttl=37 time=2.17 ms
64 bytes from 192.168.0.5 : icmp_seq=2 ttl=37 time=1.44 ms
64 bytes from 192.168.0.5 : icmp_seq=3 ttl=37 time=1.68 ms
Apparently, in Windows, you can directly connect from within containers to the host using the official host ip.
In case anyone needs it (like I did), solution for Windows and WSL is same as #prayagupd mentioned for Mac OS
Create an SSH tunnel to your remote service with whatever tool you prefer to whatever port you prefer, for example 3300.
Then, from Docker container you can connect to, for example, MySQL DB on tunnel port 3300 using following command:
mysql -u user -p -h host.docker.internal -P 3300
An easy example to reproduce the situation and ssh to host
Run a container. Use --network="host
docker container run --network="host" --interactive --tty --rm ubuntu bash
Now you can access your host using localhost
Now your host machine is a Linux machine that has a public-private key file to ssh into it. So copy the contents of your private key file and reproduce the key file inside your host. (However, this is just a demonstration. This is not a good way to copy key files)
Now ssh into your host. Use localhost to access it.
ssh -i key_file.pem ec2-user#localhost

Open tcp port 5432 for postgresql mac

I want to open a tcp port (5432) on a mac server to remotely using sql.
I installed psql9.4 using brew.
Initially I tried:
Open /etc/pf.conf in a text editor.
Add a line like this:
pass in proto tcp from any to any port 5432
Save the file.
Load the changes (and test them) with:
sudo pfctl -vnf /etc/pf.conf
Reboot.
I used network utility to check if the port was opened. But no luck.
Then I downloaded IceFloor.
I added custom Rules:
pass on en0 net photo tcp from any to any port =5432 flags S/SA keep state
Also added a new custom service to PFLists Service Database:
service name: PSQL
ports 5432
Still no luck...
Any suggestions?
Thank you

The port 80 in Mac is used

We have to use port 80 for our server. But when I was trying to use it in Mac, it always said that the 80 is used, but I don't know which program uses it.
I searched it in Google, and someone said it's about apache, but I tried, which is not working. I found this: https://gist.github.com/kujohn/7209628 , but seems it's not working visiting our server by IP address.
I really don't know what's going on and how can I find out which program using port 80 and stop it.
Many thanks if anyone can help, I'm new using Mac. Thanks.
To find out what process is using port 80
go to Applications
open utilities.
open Activity Monitor.
click on the Memory tab,
look at the ports and the processes using them. Find port 80 and select it
go to the view on the menu bar and choose Quit process.
This will just kill the process, it will not stop a server instance that is already running from continuing to run.
(Correction: the Ports column shows the number of open ports (and files?), not the port number)
It is not clear if you are using a database management system or not and which one but one method that has worked for me using MAMP is as follows.
stop the server by using sudo apachectl stop command.
then change the port to port 80.
then restart your servers.
type the following in Terminal
sudo lsof -i -n -P | grep TCP
you will get a list - e.g. dropbox listens on 80
you can copy the output to a text editor, etc to search
On Mac ports below 1024 can only be bound by the root user.
Try launching your server as root user (with sudo), or try to use a port above 1024.
You can also try to add root permissions to your user in /etc/sudoers
# root and users in group wheel can run anything on any machine as any user
root ALL = (ALL) ALL
%admin ALL = (ALL) ALL
your_user_here ALL = (ALL) ALL
I was having this issue, apache was disabled via launchctl, but was still tying up port 80 after launch, I could start up apache and it would work, but after unloading it, I couldn't start up anything on port 80. I was using the built in web server for Python as an easy test. It would work on port 81, but not on port 80.
sudo python -m SimpleHTTPServer 80 -- wouldn't work
sudo python -m SimpleHTTPServer 81 -- would work
Here are the symptoms:
$ launchctl unload -w /System/Library/LaunchDaemons/org.apache.httpd.plist
/System/Library/LaunchDaemons/org.apache.httpd.plist: Could not find specified service
$ sudo lsof -i ':80'
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
Python 3353 root 3u IPv4 0xe455777a82799f05 0t0 TCP *:http (LISTEN)
The fix for me (after way too much searching) was simple:
sudo pfctl -F all
This flushed the packet filter, releasing port 80 (and others I assume 8080, 443, whatever ports apache might be tying up)
After that, and relaunching the python server, it came right up.
Might be Skype that is using port 80. If you have Skype installed and running try to change to a different port in the settings.
Port numbers in the range from 0 to 1023 are classified as 'well-known' and port number 80 is reserved for HTTP. Typically you have servers listening on port 80 to handle HTTP requests.
Source:
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

How to open incoming port 50070 in firewall (google compute engine)

I have my Single node Hadoop installed on Google Compute Engine instance and i want to open port 50070 on that machine to access the hadoop dashboard. i configured in the firewall rule as tcp:50070 in compute engine networks. but still i am unable to access my port outside the network (ie . via internet). I tried nmap for the public ip of my GCE instance and i got a result which has only ssh port got opened all other ports are filtered .
Note: i am using debian 7.5 image
Make sure your daemon is listening on port 50070. If you have more than one networks in you project make sure the port is opened on the right network. You can run the following commands to check the information about your instance and network.
lsof -i
gcutil --project= getinstance
gcutil --project= listnetworks
gcutil --project= listfirewalls
gcutil --project= getfirewall
Check if IP/Port is allowed in iptables or not.
iptables -L
would show you all the records.
To allow port in iptables you can do the following:
sudo iptables -A INPUT -p tcp -m tcp --dport 50070 -j ACCEPT
sudo iptables-save -c
Short answer
In addition to configure the firewall rule at GCE web console make sure that your server is listening at 0.0.0.0 instead of 127.0.0.1
Long answer
In the context of servers, 0.0.0.0 means all IPv4 addresses on the local machine. If a host has two IP addresses, 192.168.1.1 and 10.1.2.1, and a server running on the host listens on 0.0.0.0, it will be reachable at both of those IPs - Source
In contrast 127.0.0.1 is the IP address used to stablish a connection to the same machine used by the user this address is usually referred as the localhost.
It's often used when you want a network-capable application to only serve clients on the same host. A process that is listening on 127.0.0.1 for connections will only receive local connections on that socket. - Source
Hence, if you try to stablish a connection to your server from internet and your server is listening at 127.0.0.1 at your GCE machine, then, from the server point of view a request has never been received and as a consequence Goocle Cloud Firewall will refuse the connection because there is no server listening at the opened port (in your case 50070).
I hope this answer helps to solve your problem. Best regards.

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