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.
Related
I have shut down iptables for my server, inspite of that when I check on http://www.yougetsignal.com/tools/open-ports/ it says my ports are not open.
Where do I have to specify to open ports. I am running a linux server
Is your server/PC behind a NAT router? If so, you may need to port forward the required ports to your server/PC. A helpful website for guides on how to do so (as it depends on your router model) is http://portforward.com/
If your server is not behind a NAT router or if you've verified you're port forwarding, is the application that's supposed to be listening on the specific port even running? Try this:
netstat -anp | grep <port number>
Netstat manual page: http://linux.die.net/man/8/netstat
If you can't find the port as listening on netstat, make sure that the application is running.
You need a server program (daemon) running on a machine listening on a port for that port to be open.
Setup the 'nmap' package on your server with 'yum install nmap -y' and check listening ports on your server:
nmap localhost
If you can see your port listening then you need to check your router for proper port forwarding, else you need to make sure that your application is working and listening for the port.
For the example, Apache2 will listen for port 80 by default.
I am currently trying to open port 8787 for rstudio server. I have set this up on an ubuntu host, and want to point my browser at the ip address of the ubuntu host, using port 8787 to direct it to rstudio. I can do this from the host machine, but no such luck using a different computer.
When I do
netstat - peantl | grep ":8787"
I get nothing returned, unlike when checking port 22 which is confirmed as listening. I can there ssh from external machines into the ubuntu host.
So I tried to open up port 8787 with iptables:
sudo iptables -A INPUT -p tcp --dport 8787 -j ACCEPT
command runs fine, but then re-checking with netstat I still do not get any output (I was expecting similar output to port 22 as mentioned previously)
I also allowed port 8787 on ufw:
sudo ufw allow 8787
using gufw it confirms port 8787 is open.
What could be the issue? If my network has restricted port 8787 how can I tell? Am I allowing port 8787 correctly with iptables?
Thanks.
All your iptables and ufw commands are doing is opening ports in the firewall itself. The fact that there is no output from the netstat|grep line means that the rstudio software does not actually have the port open for anyone to connect to. This is the issue you need to fix first.
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.
When i run the jboss-cli.sh,
I get this message.
[root bin]# sh jboss-cli.sh
You are disconnected at the moment. Type 'connect' to connect to the server or 'help' for the list of supported commands.
[disconnected /] connect localhost
The controller is not available at localhost:9999
[disconnected /] connect
The controller is not available at localhost:9999
[disconnected /] connect localhost:9999
The controller is not available at localhost:9999
[disconnected /]
Also i have another installation of jboss5 GA. I hope that is not interfering.
Although that is totally shut down for now.
Native management interface is :9999 in standalone.sh
Please throw light on this issue.
#
EDITED
#
When i stop my service with "service jboss stop"
i get this message
[root# bin]# *** JBossAS process (7302) received KILL signal ***
grep: /var/run/jboss-as/jboss-as-standalone.pid: No such file or directory
I Dont know how to check whether server is listening on the port 9999 or not.
Few more details
[root bin]# netstat -anp |grep 9999
tcp 0 0 127.0.0.1:9999 0.0.0.0:* LISTEN 7931/java
[root bin]# netstat -anp |grep 8080
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 7931/java
JBoss processs id and the server id acquiring these ports is same.
This question has two issues ,
First, i have provided debuging parameter in the startup script.
If you see 8787 that means you have somewhere provided debuging argument.
Second and the most important one controller not available #localhost or #IPADDRESS .
Please check if you have used port offset, as it increments all the ports by the number with with you have set port offset.
Suppose port offset is 2
Then try to access connect localhost:10001 Port i.e 9999+2
On my production server sometimes it does not works with localhost , but works with IP address.
Then try to access connect IPADDRESS:9999
OR
Then try to access connect 127.0.0.1:9999
Please check in the firewall weather the port 9999 or what ever with port offset, if the port is not open in the firewall it gives error,
I asked this question 6 months back and the above checks has solved
the problem always.
This is probaby because you have changed your binding configuration and jboss does not bind to 127.0.0.1.
In case your jboss instance is not binding to 127.0.0.1, you may use --controller option as follows:
./jboss-cli.sh --controller=YOUR_IP:9999
Use netstat -anp |grep 9999 to find out if port 9999 is in use and by which process id. You could also check the host.xml used by the controller to configure the proper native port.
In the host xml, you should find the default port:
<native-interface security-realm="ManagementRealm">
<socket interface="management" port="${jboss.management.native.port:9999}"/>
./jboss-cli.sh --controller=localhost:9999 --connect
You open the debug-port with jboss-cli.sh. Either you activated in jboss-cli.sh:
# Sample JPDA settings for remote socket debugging
# JAVA_OPTS="$JAVA_OPTS -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n"
or you set JAVA_OPTS with such an option in you environment. See
echo $JAVA_OPTS
I guess you did this for two jboss-processes, and you get a port-conflict. See
netstat -nap | grep 8787
I recently faced this issue and the root cause that I found was completely different than it is listed above. It is because for some other project I shifted to JDK 1.8 from 1.7. Boom! and error started coming up...I took hell lot of time figuring out why it is coming up before finally realizing I changed my JDK version.
It might be because JBOSS 7 doesn't work with 1.8 of which I have limited knowledge but yes this might prove useful for some cases.
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