I have searched for how to close psql port for a while, but most of the answers are talking about closing psql command line using \q, which is not what I am looking for.
My problem is, the postgresql on my laptop are running and listening on port 5432, but I would like to use port 5432 for some other use. Usually I run netstat -plnt to find the process to kill, but in this case the process that is listening on port 5432 does not have a process id...
Any idea on how I can release the port 5432?
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN -
psql is a client that connects to postgres server. closing connection with \q just finishes session. When it happens, backend for that session stops, so by closing connection you only release pid on server. And server keeps on listening on port 5432.
If you want to stop listening on port 5432, you can either stop postgres server with pg_ctl stop or even assign different port to it in postgres.conf, so you can run both programs in parallel
update
If you installed from packages (Ubuntu/Debian/Fedora/RHEL/CentOS/etc) you should use the system services manager to stop postgresql. e.g. in RHEL 7 or Fedora, sudo systemctl stop postgresql-9.6 (or whatever your version is) rather than pg_ctl (quoting Craig Ringer)
Related
How can I use the port 80 on my local Linux machine as the port of my node server?
The netstat command netstat -ptuln says the following about this port, while the node server is running:
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:80 0.0.0.0:* LISTEN -
I found on this site some recommendations for the command sudo iptables -I INPUT -p tcp -m tcp --dport 80 -j ACCEPT. I executed this command but when I make a request with curl (curl 1.97.xxx.xxx.xx) it keeps responding with curl: (7) Failed to connect to xxxxxx port 80: Connection refused.
But using curl the following ways works: curl 0.0.0.0:80 or curl localhost:80.
My conclusion is, that I somehow have not opened the port correctly, but all I could find on the internet repetitively is the command I mentioned earlier.
I am aware of the fact that I could fix this easily by using an apache server, but I would like to make it without it.
Thank you!
Paste the output from
netstat -ptuln
command.I think the problem is that your web server runs on local address and can not be reachable for other machines in network.
When I'm trying to run a service (RavenDB) on port 8080 it stops and the Windows Logs show the following error:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Net.HttpListenerException: Failed to listen on prefix 'http://+:8080/' because it conflicts with an existing registration on the machine.
Acccording to IIS and netstat -an | find "8080" the port is currently not in use.
If I change the port to any other, the problem disappears.
Port 8080 may actually be in use. To replicate another answer
netstat -a only lists connected sockets and listening socket.
-a Displays all connections and listening ports. Neither
connect nor listen was called on your socket, so it falls outside the
purview of netstat -a.
However, since Windows 10, you can use netstat -q.
-q Displays all connections, listening ports, and bound
You could also try to view the port using tcpview from the SysInternals suite. Sort by port number. It will also tell you the process using the port, which you can then kill.
I have a Node server hosted on an EC2 instance that is trying to connect to Postgres running on the same instance. When I start the server I get an ECONNREFUSED error to the db:
Unable to connect to the database: SequelizeConnectionRefusedError: connect ECONNREFUSED x.x.x.x:5432
I am using the Sequelize ORM package from NPM:
import Sequelize from 'sequelize';
const db = new Sequelize('postgres://postgres#52.9.136.53/unloadx' {dialect: 'postgres'});
Postgres is running on the instance, and I have port 5432 open in my inbound security rule. I can confirm that postgres is running with ps aux | grep postgres which shows multiple postgres related processes, and netstat -anp --tcp confirms that postgres appears to be listening on the port:
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp6 0 0 ::1:5432 :::* LISTEN -
But when I scan the port with nmap x.x.x.x -p 5432 it shows that the port status is closed. Per nmap, this means that the port is accessible but has no application listening on it able to respond to packets.
Appreciate any help in getting the connection to work.
One problem is that you are using the public IP address. That means your database connection is basically going out to the internet and back. This will prevent the Security Group rule from working, and introduce security and latency issues.
If you were trying to connect from another server in the VPC you would want to connect using the private IP. However, since it's on the same instance you can delete the Security Group rule and just use localhost or 127.0.0.1.
What makes you think that netstat is showing that postgres is listening on the port? If it were, you'd see something in the PID/Program column.
Also, if your postgres server is running on the same box as your node app, you should not need to open up the port to the internet via your AWS security rules, and probably shouldn't unless you need to access it from elsewhere. Then you can change your connection string to hit localhost or 127.0.0.1
Finally, verify that you've setup your postgres server correctly via the docs
My laptop is running a local neo4j server. I can use it with localhost:7474 but when i try connecting it with 192.168.1.12:7474 it is unreacheable.
Turns out linux is blocking connections other than web server port 80. Because i can access my Apache server on 192.168.1.12/
I am trying to allow TCP connections on port 7474 by using
iptables -A TCP -p tcp --dport 7474 -j ACCEPT
but it gives a response as -
iptables: No chain/target/match by that name.
How can i make other clients access neo4j server running at my laptop on port 7474. My laptop IP addr is 192.168.1.12.
I doubt that it is blocking it. Probably your neo4j server is only running at 127.0.0.1. You can check this out with netstat -nplt: you will probably see something (the apache) listening on 0.0.0.0:80 or :::80 (e.g. catchall address) but on port 7474 you will probably only see 127.0.0.1:7474 or ::1:7474. If this is the case you need to reconfigure your neo4j server to listen not only on localhost (don't know how, checkout the documentation).
Okay. I had uncommented the webserver address line but it still wasn't working.
So i reinstalled neo4j. That solved it. Weird but worked.
Sorry in advance for such a noob question, but I'm certainly a noob.
My question is what does it mean to LISTEN or ACCEPT on a port as it relates to my example?
EXAMPLE:
I have a tomcat server, and It will use port 8080. I want to make sure that port is available for me to use.
What commands should I perform on my unix server and why?
what information would a command like this give me: netstat -an | grep LISTEN
If a port shows up as LISTEN in netstat, it means the port is in use by a server process, so you can't use it. Here is an example:
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
which shows that port 631 is in use.
Ignore the UNIX type sockets at the end - they are irrelevant.
For checking port 8080 is in use or not, you can simply use the command netstat -an|grep 8080. If you get an output in below format, that means 8080 is already in use and you need to assign a new port for the tomcat.
# netstat -an
tcp 0 0 127.0.0.1:8080 0.0.0.0:* LISTEN
Netstat command displays various network related information such as network connections, routing tables, interface statistics, masquerade connections, multicast memberships etc,
a option with netstat will give you both listening and non listening ports
n option when you don’t want the name of the host, port or user to be displayed, use netstat -n option. This will display in numbers, instead of resolving the host name, port name, user name. This also speeds up the output, as netstat is not performing any look-up.
For more understand the use of netstat command here are its options:
-a : All ports
-t : Ports TCP
-u : Ports UDP
-l : Listening ports
-n : IP address without domain name resolution
-p : Name of the program and it associated PID
So:
-To display all port (TCP & UDP), PId with the associated name of the program :
$ netstat -paunt
-To display all Listening ports (TCP), PId with the associated name of the program : (and we can also filter with the grep command)
$ sudo netstat -plnt | grep ':80'
I hope it will be helpful :)
You can also use telnet to check if the port is open and listening e.g,
Zeeshan$ telnet google.com 80
Trying 173.194.35.5...
Connected to google.com.
Escape character is '^]'.
I am telnetting google.com on port 80. If you see the third line in the output, you will notice it says it is connected with the Google's web server. The same way you have a JAVA application server called Tomcat and it is listening on port 8080. In fact it is asking clients to connect to it on port 8080 so it can give away the JAVA services to client. When I will use from a client side telnet localhost 8080 I will be connected the same way I have connected with Google's web server on port 80. Provided that Tomcat is running and listening on port 8080. If port 8080 is not free and occupied by some other application you can simply change the port 8080 to another free port. Telnet should give you the following status:
accepted (connected), refused, and timeout
connection refused - nothing is running on that port
accepted - some application is running on the port
timeout - a firewall is blocking access
So now there are two possible ways to check. From the same machine you are running Tomcat server:
telnet localhost 8080
Of if you want to check it from some other machine or outside of the network:
telnet 192.168.1.1 8080
I hope that helps.
use can also run the below command, it will list the Port and corresponding PID, if any process is using those ports
netstat -tulpn