how to open port 8080 for listening when firewall is not running

nasridine · 09-19-2014, 01:26 PM

We have an internal cluster that runs on Centos. We do not turn on iptables purposefully. I am developing some web application which needs to talk to localhost through port 8080. However telnet 127.0.0.1:8080 could not connect. Is there a way to open port 8080 for listening without messing with the firewall?

We do not intend to turn on firewall. So commands like this is not an option:
iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

suicidaleggroll · 09-19-2014, 01:36 PM

There has to be some application listening for connections on port 8080, what do you want that application to be/do?

Habitual · 09-19-2014, 01:37 PM

What's listening on 8080?
Something has to 'answer' for

Code:

telnet 127.0.0.1 8080

to 'work'.

Code:

lsof -i :8080

can be used to show what's serving on port 8080

schneidz · 09-19-2014, 01:44 PM

i would set the port number in /etc/ssh/sshd_config to 8080 then restart sshd.

or maybe hax something up like this:

Code:

[schneidz@hyper ~]$ cat ./stuff/netcat.ksh
#!/bin/bash
PL=$(find /root/user/music -name "*.mp3")
NUM=$(echo $PL |wc -w)
{
while true; do
r=$(($RANDOM%$NUM))
s=$(echo $PL |cut -d ' ' -f$r)
echo "HTTP/1.0 200 OK\nContent-Type: audio/x-mp3stream\n\n"
dd if=$s bs=1024
done
} | nc -l -s address -p 8080

nasridine · 09-19-2014, 01:44 PM

Quote:

Originally Posted by suicidaleggroll

There has to be some application listening for connections on port 8080, what do you want that application to be/do?

I tried to run some simply jersey application which needs to talk to http://localhost:8080

nasridine · 09-19-2014, 01:46 PM

Quote:

Originally Posted by Habitual

What's listening on 8080?
Something has to 'answer' for

Code:

telnet 127.0.0.1 8080

to 'work'.

Code:

lsof -i :8080

can be used to show what's serving on port 8080

connection refused for telnet command. "lsof -i :8080" returns nothing

nasridine · 09-19-2014, 01:48 PM

Quote:

Originally Posted by schneidz

i would set the port number in /etc/ssh/sshd_config to 8080 then restart sshd.

or maybe hax something up like this:

Code:

[schneidz@hyper ~]$ cat ./stuff/netcat.ksh
#!/bin/bash
PL=$(find /root/user/music -name "*.mp3")
NUM=$(echo $PL |wc -w)
{
while true; do
r=$(($RANDOM%$NUM))
s=$(echo $PL |cut -d ' ' -f$r)
echo "HTTP/1.0 200 OK\nContent-Type: audio/x-mp3stream\n\n"
dd if=$s bs=1024
done
} | nc -l -s address -p 8080

In the current /etc/ssh/sshd_config, Port line is commented out.

schneidz · 09-19-2014, 01:48 PM

is telnetd running ?; you should probably try running sshd instead.

^ what happens when you uncomment it (changing it to 8080) and restart the ssh server ?

suicidaleggroll · 09-19-2014, 01:50 PM

Quote:

Originally Posted by nasridine

I tried to run some simply jersey application which needs to talk to http://localhost:8080

localhost:8080 is not a destination, it's a path. There has to be something on the other side of that path for your jersey application to connect to. When you open the connection, your jersey application is not talking to localhost:8080, it's talking to some other application through localhost:8080.

So, what application is it supposed to connect to? telnetd? sshd? apache? some custom program?

suicidaleggroll · 09-19-2014, 01:51 PM

Quote:

Originally Posted by schneidz

is telnetd running ?; you should probably try running sshd instead.

^ what happens when you uncomment it (changing it to 8080) and restart the ssh server ?

What leads you to believe it's sshd that he wants to connect to? I haven't seen him mention any server application that he wants to connect to yet, apart maybe from telnetd since that's the client he's trying to use.

schneidz · 09-19-2014, 01:58 PM

what is jersey application.

i was answering in general the process to configure any server to listen to a particular port. ssh and netcat just seemed like easy examples.

nasridine · 09-19-2014, 02:07 PM

Quote:

Originally Posted by suicidaleggroll

localhost:8080 is not a destination, it's a path. There has to be something on the other side of that path for your jersey application to connect to. When you open the connection, your jersey application is not talking to localhost:8080, it's talking to some other application through localhost:8080.

So, what application is it supposed to connect to? telnetd? sshd? apache? some custom program?

Sorry, I did not understand the question. It is connecting to a grizzly container. https://grizzly.java.net/

suicidaleggroll · 09-19-2014, 02:09 PM

Have you started this grizzly container, with it configured to listen on port 8080?

nasridine · 09-19-2014, 02:22 PM

Quote:

Originally Posted by suicidaleggroll

Have you started this grizzly container, with it configured to listen on port 8080?

I don't think I need to configure the Grizzly (or maybe I am wrong). Basically following the Jersey tutorial here.
https://jersey.java.net/nonav/docume...ject-structure

Running this simple example did not have any error. Only when I tried to communicate with the resource using "curl http://localhost:8080/myapp/myresource", it complained "couldn't connect to host".

suicidaleggroll · 09-19-2014, 02:27 PM

You'll need to start up grizzly at some point. The documentation you posted has this little nugget buried in it

Quote:

Now that we have verified that the project compiles and that the unit test passes, we can execute the application in a standalone mode. To do this, run the following maven command:

mvn exec:java

The application starts and you should soon see the following notification in your console:

May 26, 2013 8:08:45 PM org.glassfish.grizzly.http.server.NetworkListener start
INFO: Started listener bound to [localhost:8080]
May 26, 2013 8:08:45 PM org.glassfish.grizzly.http.server.HttpServer start
INFO: [HttpServer] Started.
Jersey app started with WADL available at http://localhost:8080/myapp/application.wadl
Hit enter to stop it...
This informs you that the application has been started and it's WADL descriptor is available at http://localhost:8080/myapp/application.wadl URL. You can retrieve the WADL content by executing a curl http://localhost:8080/myapp/application.wadl command in your console or by typing the WADL URL into your favorite browser.

See the part in bold. Those messages indicate that grizzly has been started and is listening on port 8080.