1 Reply Latest reply on Feb 29, 2012 6:04 AM by petal1

    JNDI not resolving localhost to 127.0.0.1

    petal1
    petal1 Feb 27, 2012 11:48 AM

      Hello,

       

      I have an Amazon EC2 instance (could be any cloud server, or even any server I guess) running Open SuSE. I am running JBoss 4.0.4GA on there. When I do a JNDI lookup with a provider URL of "localhost:1099", I may get an error depending on what is in /etc/hosts.

      What I don't understand is why JBoss is not resolving localhost to 127.0.0.1.

       

      When /etc/hosts contains:

          127.0.0.1              localhost

          <external-ip-not-shown>  MYHOSTNAME

       

      then JBoss resolves localhost to the external IP. If the /etc/hosts file contains:

          127.0.0.1              localhost

          <internal-ip-not-shown> MYHOSTNAME

       

      then JBoss resolves localhost to the internal IP.

       

      So clearly /etc/hosts is involved in JBoss’s resolution of names. But when I do:

      dig localhost +short +identify

      It returns:

      127.0.0.1 from server 172.16.0.23 in 80 ms.

       

      Apparently Amazon EC2 instances don't have any awareness of their external IP, so the /etc/hosts should reference only the internal IP address. Indeed my application works fine when the /etc/hosts file contains only the internal IP but my issue is why JBoss does not resolve localhost to 127.0.0.1 ?

       

      Just as a bit of extra info, I executed the code below:

          InetAddress ina= InetAddress.getByName("localhost");

         System.out.println("getCanonicalHostName()=" +ina.getCanonicalHostName());

         System.out.println("getHostAddress()=" +ina.getHostAddress());

         System.out.println("getHostName()=" +ina.getHostName());

         System.out.println("toString()=" +ina.toString());

       

      and it returned:

           getCanonicalHostName()=localhost

           getHostAddress()=127.0.0.1

           getHostName()=localhost

           toString()=localhost/127.0.0.1

       

      Thank you for any help.