When I run my spring boot project through IDE works fine and perfect,
But when I try to deploy it on Digital Ocean's droplet it throws an Exception :
SQLNonTransientConnectionException: Socket fail to connect to host:address=(host=127.0.0.1)(port=3308)(type=primary). Connection refused
And i'am pretty sure about the credential ; It already went fine on my IDE .
This is not a credential issue, "Connection refused" is the java standard message when a socket fails to establish, so the problem is before authentication.
The problem is either nothing is listening on the IP:Port you are trying to connect to or the port is blocked by a firewall.
check that loopback 127.0.0.1 is defined with command like :
ip addr show lo
run
sudo netstat -tnlp | grep :3308
to ensure that something is listening on port.
expected answer are like :
tcp 0 0 0.0.0.0:3308 0.0.0.0:* LISTEN 76468/mariadbd
tcp6 0 0 :::3308 :::* LISTEN 76468/mariadbd
Related
I got a webserver running on my Mac on localhost:3000 and I am trying to set a local DNS with dnsmasq and to be able to access that DNS from local devices (iPhone / iPad) for test purpose.
I followed this previous post:
iPhone: add entry to /etc/hosts without jailbreaking
I am looking to redirect all *.localhost here
dnsmasq.conf:
/etc/resolver/localhost:
dig google.com:
The Mac Network DNS config:
On my phone, on the same network, adding the Mac Local IP as DNS:
Wi-Fi is connected to xxxxxx and has the IP address 192.168.1.11.
I am able to connect to myapp.localhost:3000 successfully on the Mac but getting Server cannot be found on the iPhone.
Must be missing something there.
EDIT #0: 2021/07/08
netstat -anvp tcp | grep '\b192.168.1.11.53\b' output:
open a terminal and use netstat to check if your dnsmasq is open on 192.168.1.11
if the result is similar to
root#dns-01:~# sudo netstat -tnlp
tcp 0 0 127.0.0.1:53 0.0.0.0:* OUÇA 13376/dnsmasq
it means that it will only accept queries from the local machine, not from your network.
to query from your network you must see something like
tcp 0 0 192.168.1.11:53 0.0.0.0:* OUÇA 13376/dnsmasq
or
tcp 0 0 0.0.0.0:53 0.0.0.0:* OUÇA 104287/dnsmasq
I'm trying to connect to a WebSocket server (PHP / Wrench) running on my webserver.
The configuration of the server looks like this:
$server = new \Wrench\Server("wss://localhost:8443");
$server->registerApplication('app',
new \Wrench\Application\EchoApplication());
$server->run();
I'm using port 8443 because I can't use 80 or 443 (Permission denied). The domain uses HTTPS so I have to use the wss: protocol.
I have no problem connecting to the PHP server when I run the script on my local machine (I just have to replace wss: by ws:).
When I run the server via SSH on my remote webserver, it seems to run correctly, but trying to connect to it via JS with the following call doesn't work:
var ws = new WebSocket("wss://dev.mydomain.net:8443/app");
I get an "Error in connection establishment: net::ERR_CONNECTION_REFUSED."
On my webserver panel control, the 8443 port (TCP) is open (in and out). When the PHP server is running, the command netstat -a | grep 8443 gives the following output, which I think should confirm it's open:
tcp 0 0 localhost:8443 *:* LISTEN
Is there an obvious detail I'm missing here?
I finally found a solution: instead of setting the URI of the server to localhost, I had to use 0.0.0.0. Now it works perfectly when I'm using HTTP (there's another problem when using HTTPS, but at least I have more information at this point).
I went through all these error questions that I could find on SO and I've done everything that it appears I should do. Still, I get connection refused when I telnet to port 25
This is what is asked for in other questions:
netstat-an | grep LISTEN
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:53045 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN
tcp 0 0 :::111 :::* LISTEN
tcp 0 0 :::80 :::* LISTEN
tcp 0 0 :::22 :::* LISTEN
tcp 0 0 :::443 :::* LISTEN
tcp 0 0 :::52266 :::* LISTEN
So, port 25 is listening. Next, can I telnet to 25 on localhost? Yes. No problem. I can do localhost and I can do it with 127.0.0.1 and I can do it with the proper IP address. As long as I am on the machine itself, I can telnet to port 25.
Next, the EC2 firewall. There are two levels, iptables and the EC2 security zone. I made sure iptables and ip6tables were shut down. Service shows that both are "Firewall is not running". I checked the EC2 security zone. It shows:
25 tcp 0.0.0.0/0
So, it is allowing all traffic to port 25.
Still, I get connection refused when I telnet to port 25.
I continued. I checked /etc/hosts.allow and /etc/hosts.deny. Both are empty.
I continued. I looked in the mail folder. The domain is in local-host-names (which doesn't matter since I never get to the point of entering a recipient email address). I don't see anything about blocking or allowing hosts. Perhaps there is something buried in the cryptic sendmail.cf file. So, I wanted to ensure that sendmail was definitely listening with
lsof -i :25
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sendmail 11457 root 4u IPv4 830292 0t0 TCP *:smtp (LISTEN)
Same as netstat. Listening on all devices on port smtp (25).
So, I am at a loss. Why would I get connection refused on port 25? It isn't unable to reach server. It isn't that it is not listening. It is clearly that it is listening and refusing connections.
The problem here is that there are two issues:
1) Many ISPs block outbound port 25 requests. So, it is rather common that telnet somedomain.com 25 will fail and report something like "denied" or "unreachable."
2) Proper programs that go out on port 25 are mail programs. A mail program is designed to send email to your email service, which then uses the MX record for the domain name to deliver the email. What I found is that when you register a domain name with Network Solutions and set "All" IP addresses to be a certain address, they do NOT set the MX record address. That remains set to Network Solutions' mail server. So, if someone uses a proper email program to hit your domain name, it will go to mx.yourdomain.com, which may not be your server.
In my case, I had to manually set the IP address for the mx record with Network Solutions. Then, I magically started getting emails.
For those that don't know how to check MX records, in Linux, you can run dig domain.name MX. However, it isn't your MX record setting that matters. It is your mail server's setting. For example, if my computer says the mx record is 12.34.56.78 and I use GMail and Google says the mx record is p.ctmail.com, then sending email through GMail will fail.
today i installed a vncserver on my raspberry pi running rasbian.
I used this tutorial: http://blog.wenzlaff.de/?p=2207 (its german but i think you will understand what they do there anyway ;) )
Everythin worked great but the tightvnc viever jar applet on my mac will not go further than "handshaking with remote host". After typing in my password of my pi, nothing is happening anymore.
I tried to look in the logs of tightvncserver on the pi , but i got a "permission denied" every time.
Can you help me please. I dont know what do to now.
Thanks
Most likely you have some problems with SSH-tunneling ( provided you were following the tutorial).
To diagnose what's happening, first it would be nice to figure out whether your vncserver is running on Raspberry. You can do it by issuing command:
netstat -lnt
The output can look something like below:
pi#raspberrypi ~ $ netstat -lnt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:587 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:5901 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6001 0.0.0.0:* LISTEN
We are interested to see if there's line:
tcp 0 0 0.0.0.0:5901 0.0.0.0:* LISTEN
which basically tells us that our vncserver instance is listening on port 5901.
If that's true, then you should be able to use any VNC Viewer to connect to your RPI. Maybe you want to avoid SSH-tunnelling option and connect directly.
I created web socket test app with tornado server and static html page for check connection to this server.
When I try to connect from localhost to websocket, it works fine. if I try to connect from remote IP, I get "connection closed by timeout".
netstat -lnp gives me next result:
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 14837/python2.7