I'm testing gRPC with .NetCore and looked up for a GUI tool or something that can help me to test my endpoint like testing REST API.
I found a proxy tool: grpc-json-proxy that can be used with Postman tool (also found another GUI tool: grpcox).
Using any tool gives an error like the following when trying to connect to the endpoint:
unable to do request err=[Post
http://localhost:5001/greet.Greeter/SayHello: dial tcp 127.0.0.1:5001:
connect: connection refused]
Any idea what could be the issue?
Most importantly, are you confident the gRPC server is listening on localhost:50051? You may confirm this (on Linux) using:
GRPC="50051"
ss --tcp --listening --processes "sport = :${GRPC}"
NOTE you may need to sudo ss ... to get the process
Or more simply:
telnet localhost 50051
If you get Connected to... that's a good sign
Then, if you're using either of these tools through docker, you'll need to ensure the container can access the host's 50051 port. To do this, run the container use --net=host. This will make the host's port available to the container.
I use grpCurl
I am looking to use asyncssh with python3.7 (asyncio)
Here is what I want to build:
A remote device would be running a client that does a call-home to a centralized server. I want the server to be able to execute commands on client using reverse ssh tunnels on the incoming connection. I cannot use forward ssh (regular ssh) because the client could be behind NAT and server might not know the address of the client. I prefer client doing a call-home and then server managing the client.
The program for a POC should use python3 + an async implementation of ssh. I see asyncssh as the only viable choice (please suggest if you have an alternate):
Client: Connect to server and accepts reverse ssh tunnels to be opened on same outbound connection
Server: Accepts connection from client and keeps the session open. The server then opens reverse ssh tunnel to the client. For e.g. the server program should open 3 reverse ssh tunnnels on the incoming connection. Each of these tunnels would run one command ['ls', 'sleep 30 && date', 'sleep 5 && cat /proc/cpuinfo']
Server program should print the received response for each of these commands (one should come back amost immediately, other after 5 and other after 30).
I looked at the documentation, and I could not see examples of using multiple reverse ssh tunnels.
Anyone has experience using this? Can you point me to examples?
Developer of asyncssh has provided an example:
As of now, this is in develop branch. I have tested it and it does the job perfectly!
https://asyncssh.readthedocs.io/en/develop/#reverse-direction-example
[If you are checking this after a while, you might find it in master documentation.]
I'm trying to use Google's Colab feature to connect to a remote run-time that is configured with HTTPS. However, I only see an option to inform the port on the UI, not the protocol.
I've checked the Network panel and the website starts a WebSocket connection with http://localhost:8888/http_over_websocket?min_version=0.0.1a3, HTTP-style.
Full details of my setup:
I have a public Jupyter server at https://123.123.123.123:8888 with self-signed certificate and password authentication
I've followed jupyter_http_over_ws' setup on the remote
I started the remote process with jupyter notebook --no-browser --keyfile key.pem --certfile crt.pem --ip 0.0.0.0 --notebook-dir notebook --NotebookApp.allow_origin='https://colab.research.google.com'
I've created a local port forwarding with ssh -L 8888:localhost:8888 dev#123.123.123.123
I've turned on network.websocket.allowInsecureFromHTTPS on Firefox
I've went to https://localhost:8888 and logged in
Naturally, when the UI calls http://localhost:8888/http_over_websocket?min_version=0.0.1a3 it fails. If I manually access https://localhost:8888/http_over_websocket?min_version=0.0.1a3 (note the extra s) it gets through.
I see three options to solve it:
Tell the UI to use secure WS connection
Run a proxy on my local machine to transform the HTTPS into plain HTTP
Turn off HTTPS on my remote
The last two I think will work, but I wouldn't like that way.
How to do #1?
Thanks a lot!
Your option 1 isn't possible in colab today.
Why do you want to use HTTPS over an SSH tunnel that already encrypts forwarded traffic?
I am getting error:
"Lost connection to MySQL server at 'reading initial communication packet, system error: 0"
while I am going to connect my db.
If I am using localhost everything is working fine.
But when I am using my live IP address like below, it's getting error:
mysql_connect("202.131.xxx.106:xxxx", "xxxx", "xxxxx") or die(mysql_error());
Someone here suggests that it might be a firewall problem:
I have just had this problem and found it was my firewall. I use PCTools Firewall Plus and it wasn't allowing full access to MySQL. Once I changed that it was fine.
Could that be it?
Also, someone here suggests that it might be because the MySQL server is bound to the loop-back IP (127.0.0.1 / localhost) which effectively cuts you off from connecting from "outside".
If this is the case, you need to upload the script to the webserver (which is probably also running the MySQL server) and keep your server host as 'localhost'
Open mysql configuration file named my.cnf and try to find "bind-address", here replace the setting (127.0.0.1 OR localhost) with your live server ip (the ip you are using in mysql_connect function)
This will solve the problem definitely.
Allow remote connect to MySQL.
Edit file:
>sudo nano /etc/mysql/my.cnf
Comment line:
#bind-address = 127.0.0.1
Restart MySQL:
>sudo service mysql restart
Create user for remote connection.
>mysql -uroot -p
CREATE USER 'developer'#'localhost' IDENTIFIED BY 'dev_password';
CREATE USER 'developer'#'%' IDENTIFIED BY 'dev_password';
GRANT ALL ON *.* TO 'developer'#'localhost';
GRANT ALL ON *.* TO 'developer'#'%';
In my case I need to connect remotely from Windows to VirtualBox machine with Ubuntu. So I need to allow port 3306 in iptables:
>iptables -A INPUT -i eth0 -p tcp -m tcp --dport 3306 -j ACCEPT
Had this problem when setting up a new slave server. Found it was the slave server IP address was missing from the master server /etc/hosts.allow file. Added the IP address and it let me connect to the master server.
Note that I use hosts.allow and hosts.deny to control access.
I had this problem and it ended up being the prior sys admin changed the port MySQL was running on. MySQL Workbench was trying to connect to the default 3306 but the server was running on 20300.
The error means that it didn't receive a response from the port it expected to find the server on. The causes range from contacting the wrong machine (For one of a number of reasons) to the server not being on the expected port.
Check which port your server is bound to in /etc/mysql/my.cnf. Does that correspond to what is in your connect statement. If they match then try connecting with mysql from the server itself and from the command line of the machine where you are running the client. If it works form one place and not another then you may have a firewall / router configuration issue.
One more reason...
I ran into an Ubuntu server where everything was customized and could not connect because of that same error.
This setting was inside /etc/ssh/sshd_config
PermitTunnel no
After turning into
PermitTunnel yes
I was able to connect remotely to my MySQL DB
The problem on my case was MySQL being bind only to the lo on linux.
in order to solve the problem i have edited the my.cnf (found at /etc/mysql/my.cnf) removing the line bind-address=127.0.0.1
this allows mysql to bind to any network interface
I just set up mysql on a windows box. I got the OP's error when trying to connect with the Navicat MySql client on the same box. I had to specify 127.0.0.1 as the host, and that got it.
localhost, or the servers actual ip address both did not work.
This error occurred to me while trying to connect to the Google Cloud SQL using MySQL Workbench 6.3.
After a little research I found that my IP address has been changed by the internet provider and he was not allowed in the Cloud SQL.
I authorized it and went back to work.
I faced the same problem. I checked and tried to set AllowTcpForwarding Yes but it was missing in my sshd_config so no help.I didn't change sshd_config or my.cnf. Make sure the ssh hostname is NOT the same with the mysql hostname(use localhost).
In workbench, choose + to add new connection and set the following:
connection method: standard TCP/IP over SSH
SSH Hostname: 192.168.0.50:22 (replace remote SSH server IP and port(optional))
SSH Username: sshuser
You can set password or add at the prompt
MYSQL Hostname: localhost or 127.0.0.1
MYSQL Server port:3306
You can set password or add at the prompt
Test connection. It should be successful then hit OK.Viola!
I ran into this exact same error when connecting from MySQL workbench. Here's how I fixed it. My /etc/my.cnf configuration file had the bind-address value set to the server's IP address. This had to be done to setup replication. Anyway, I solved it by doing two things:
create a user that can be used to connect from the bind address in the my.cnf file
e.g.
CREATE USER 'username'#'bind-address' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON schemaname.* TO 'username'#'bind-address';
FLUSH PRIVILEGES;
change the MySQL hostname value in the connection details in MySQL workbench to match the bind-address
The problem for me was that DNS queries were blocked by the FW within the subnet. The solution was to disable DNS lookups within MySQL.
The problem was quite stupid for me.
I used to get the same issue on AWS EC2 Ubuntu machine (MariaDB is installed locally for the time being), so I tried to make SSH tunneling, and had the same issue. So I tried to ssh tunnel over terminal:
ssh -L13306:127.0.0.1:3306 root#ip.address -i my/private/key.pem
And it told me this:
Please login as the user "ubuntu" rather than the user "root".
I changed ssh user from root to ubuntu, just like my ssh config, and it connected just fine.
So check your SSH connecting user.
I oversaw this, so this too half an hour of my time, so I hope this will be useful for you.
For me the config file was found "/etc/mysql/mysql.conf.d/mysqld.cnf" commenting out bind address did the trick.
As we can see here:
Instead of skip-networking the default is now to listen only on
localhost which is more compatible and is not less secure.
I am trying to connect my db docker container on Ubuntu 18.04, same problem.
First check your device by run nmcli dev to check if device docker0 is connected.
If it is not connected, try to restart docker service:
sudo service docker restart
I tried make a telnet over remote server on port 3306.
The error message is clear
Host 'x.x.x.x' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'Connection closed by foreign host.
As root at server mysqladmin flush-hosts worked at all!
I had the same error when using localhost. I restarted the MySQL service and it worked fine.
in my case, I had ALL: ALL in hosts.deny. Changing this to ALL: PARANOID solved my problem when connecting over ssh
Ran into this same issue, Bind Address back and forth to no avail. Solution for me was flushing privileges.
mysql> FLUSH PRIVILEGES;
Firewalld blocks the IP address. so to give access, use these commands:
firewall-cmd --permanent --zone=trusted --add-source=YOUR_IP/32
firewall-cmd --permanent --zone=trusted --add-port=3306/tcp
firewall-cmd --reload
For me setting bind-address = 0.0.0.0 in mysql/my.cnf worked. It basically listens to all addresses (but still one port) then.
And don't forget restart your server: systemctl restart mysql
I just had the same problem, but in my case I solved it with
service mysqld start
In my case it was the university wifi blocking port 3306. I was able to connect by using a mobile hotspot.
Change to a mobile hotspot or another network, and if it works there, then you know that original network is blocking port 3306. If you get the same error on more than 1 network, then you know it's specific to your machine.
I had port 3306 in Docker container but in Dockerfile it was 33060. I edited the port in Docker container to 33060
Must have been added to the Dockerfile
ENV MYSQL_ROOT_HOST 172.17.0.1
I have done below 3 steps then working for me.
bind-address = "YOUR MACHINE IP" in my.cnf file at /etc/my.cnf
Restart service by command : service mysql restart
GRANT ALL PRIVILEGES ON yourDB.* TO 'username'#'YOUR_APPLICATION_IP' IDENTIFIED BY 'YOUR_PASSWORD' WITH GRANT OPTION;
I had the same issue installing MySQL docker image then trying to connect from WSL2 MySQL client.
As it was stated in the accepted answer that it should be a firewall issue, in my case this error was caused due to not allowing docker for windows to communicate to private network.
I changed the settings on "Firewall & network protection", "allow an app through firewall", "change settings" (need administrator rights) and allowed "Docker desktop backend" to connect to private network.
I had the same error on my Mac with a local MySQL installation. The problem was that the number files that MySQL was opening was too high for MacOS.
To see if you have the same problem you can run this command and look for File Descriptor errors:
tail -200 /usr/local/var/mysql/$(whoami).err | grep "Warning"
I added this line to my.cnf file and the problem was fixed:
table_open_cache = 200
Had the same problem, what worked for me was:
Go to Windows Firewall where you allow applications.
mysql probably won't be in the list, so you need to add it, its path is typically C:/Program Files (x86)/MySQL/bin/mysql
Mark both private and public networks, apply.
When connecting to Mysql remotely, I got the error.
I had this warning in /var/log/mysqld.log:
[Warning] IP address 'X.X.X.X' could not be resolved: Temporary failure in name resolution
I just added this line to /etc/hosts file:
X.X.X.X some_name
Problem solved! Not using skip-name-resolve caused some errors in my local app when connecting to MySQL.
I'm trying to write a go application that would allow me to perform reverse ssh tunneling between a Windows machine and a Linux machine using the go ssh library.
In the process of doing so, I create a listener on the remote machine, as follows:
remoteListener, err := sshClient.Listen("tcp", remoteString)
where sshClient is an object of type ssh.Client and is configured to connect to the remote machine.
The issue here is that when the sshd process on the Linux machine disrupts the connection with the application, the ssh Listener remains alive on the remote machine. So, reconnecting with the application fails because a listener is already running on the same port on the remote machine.
How do I get around this issue? Does the ssh library allow me to define a timeout on the listener?
I'm just waiting for the timeout after reconnecting. I found no other easy solution for this.