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Display issue in linux

anappsdba Newbie
Currently Being Moderated
Hi All !

Any help on the below error please:

[oracle@test ~]$ firefox https://test.synerp.com:5500/em/console/aboutApplication
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

Error: cannot open display: :0.0
  • 1. Re: Display issue in linux
    EdStevens Guru
    Currently Being Moderated
    VinodNagpure wrote:
    Hi All !

    Any help on the below error please:

    [oracle@test ~]$ firefox https://test.synerp.com:5500/em/console/aboutApplication
    Xlib: connection to ":0.0" refused by server
    Xlib: No protocol specified

    Error: cannot open display: :0.0
    This has zero to do with the database and everything to do with your handling of the OS. I'd suggest you ask here: Generic Linux

    But it appears to me you have connected to a linux box (via an ssh client like PuTTY) and are trying to launch firefox from there for the purpose of accessing the dbcontrol on your linux box. And since you haven't set up to direct x-windows output from the linux to your desktop, it doesn't know what to do. I'd run firefox to access the same url directly from the desktop.
  • 2. Re: Display issue in linux
    anappsdba Newbie
    Currently Being Moderated
    Thanks for your reply and pointing out. Yes you are right. But I tried to connect directly from the browser too but it is not working. And my concepts are not clear on display setting. Could you please point out some good document/link for understanding the same ?

    Regards,
    Vinod
  • 3. Re: Display issue in linux
    Dude! Guru
    Currently Being Moderated
    Understanding how the X Window System works and how the DISPLAY variable relates to X-Forwarding or connecting to a local or remote X server is quite complex. X Window is not like MS Windows and based on a Client-Server architecture. The X server must be running on your local PC in order to use ssh with X forwarding. VNC is another different option.

    I think for solving your problem it should not be necessary to start a remote Firefox session on your Linux server. You should be able to display the DB console from your client PC desktop. All you probably have to do is to disable the firewall on the Linux server.

    You can try it:

    <pre>
    su - root
    service iptables stop
    </pre>

    Then connect to the URL from your desktop PC and report if it works or not.
  • 4. Re: Display issue in linux
    anappsdba Newbie
    Currently Being Moderated
    Hey thanks for your reply ! I tried after stopping the firewall but still not able to connect through the browser. :( It says cannot display the webpage.
  • 5. Re: Display issue in linux
    Dude! Guru
    Currently Being Moderated
    Perhaps the DB console is not running. You can try the following on the Linux server:

    <pre>
    su - oracle
    . oraenv
    emctl status dbconsole
    emctl start dbconsole
    </pre>

    If this is a default installation and you have NOT reconfigured the dbconsole then the default port is 1158, not 5500.

    For further resolution of the problem, for example, how to start and access the dbconsole I suggest to post your problem in the DB installation forum. Typical issues are incorrect or missing entries in /etc/hosts on the server.
  • 6. Re: Display issue in linux
    anappsdba Newbie
    Currently Being Moderated
    I have checked, dbconsole is running and the port too is correct. Perhaps the sysadmin need to do something on the server to access the link from the browser ?
  • 7. Re: Display issue in linux
    Dude! Guru
    Currently Being Moderated
    Did the sysadmin configure or stop the firewall on the server?
    Can you connect to the server using the TCP/IP address in the URL rather than the FQDN?
  • 8. Re: Display issue in linux
    anappsdba Newbie
    Currently Being Moderated
    I tried with IP address in the URL and it says Apache HTTP server is installed properly.
  • 9. Re: Display issue in linux
    Dude! Guru
    Currently Being Moderated
    Now you need to connect to the right port and it should prompt for dbconsole login
  • 10. Re: Display issue in linux
    anappsdba Newbie
    Currently Being Moderated
    First I tried http://172.20.220.15/ and it says HTTP is working fine. Next I tried http://172.20.220.15/5500 and it says The webpage cannot be found !
  • 11. Re: Display issue in linux
    EdStevens Guru
    Currently Being Moderated
    VinodNagpure wrote:
    First I tried http://172.20.220.15/ and it says HTTP is working fine. Next I tried http://172.20.220.15/5500 and it says The webpage cannot be found !
    is 'http://172.20.220.15/5500' the url that is reported when you 'emctl start dbconsole'?

    show us the full command and output of
    emctl stop dbconsole
    emctl start dbconsole
  • 12. Re: Display issue in linux
    EdStevens Guru
    Currently Being Moderated
    VinodNagpure wrote:
    Thanks for your reply and pointing out. Yes you are right. But I tried to connect directly from the browser too but it is not working.
    "it is not working. " is not an actionable error message. My car "is not working". Can you tell me what is wrong with it?

    And my concepts are not clear on display setting. Could you please point out some good document/link for understanding the same ?
    It's not necessarily that simple. For your immediate purpose, I would abandon that. dbcontrol is a web-based app. It is accessed via a web browser. It doesn't give a flying fig if the browser is running on the server or on some desktop. Far simpler to run the browser from your desktop and not have to deal with x-windows redirection at all.

    But to give you a heads up .. when you DO have to deal with x-windows output (like when running runInstaller, or dbca, or asmca) .. there are two parts to the equation.
    1 - an x-windows server running on your desktop
    2 - output redirection on the server.

    part one is achieved with any of various products. Just google 'x-server'. I use xMing. It is free, lightweight, and requires no configuration.
    part two is achieved in either of two ways. One is to set the DISPLAY environment variable to the IP address and display number of the desktop OS. So if my desktop OS is at 123.456.789.101, then "set DISPLAY=123.456.789.101:0". cASE iS iMPORTANT.
    However, since my desktop has a DHCP assigned IP address, I don't want to have to check it every time, so there is an easier solution. Using PuTTY as my ssh client, I can configure the connection definition to allow x-11 port forwarding. That eliminates the need to set DISPLAY at all. I just leave xMing running all the time. Whenever I establish a putty session to one of my linux servers, I'm already enabled to run x-windows apps.
    >
    Regards,
    Vinod
  • 13. Re: Display issue in linux
    Dude! Guru
    Currently Being Moderated
    I think though that sorting out remote or local X Window support to access the DB console is probably not a suitable solution for the OP. And it should not be necessary at all. If the network, URL addressing or the server firewall configuration is not the problem then it pretty much leaves the database DB console configuration, which is beyond the scope of this forum.
  • 14. Re: Display issue in linux
    EdStevens Guru
    Currently Being Moderated
    Dude wrote:
    I think though that sorting out remote or local X Window support to access the DB console is probably not a suitable solution for the OP. And it should not be necessary at all. If the network, URL addressing or the server firewall configuration is not the problem then it pretty much leaves the database DB console configuration, which is beyond the scope of this forum.
    True. I guess I was just anticipating his next thread .... ;-)
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