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Posted to issues@karaf.apache.org by "Grzegorz Grzybek (Jira)" <ji...@apache.org> on 2021/04/08 12:50:00 UTC

[jira] [Created] (KARAF-7096) When rmiServerHost is 127.0.0.1, RMIServerImpl_Stub still uses hostname's IP

Grzegorz Grzybek created KARAF-7096:
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             Summary: When rmiServerHost is 127.0.0.1, RMIServerImpl_Stub still uses hostname's IP
                 Key: KARAF-7096
                 URL: https://issues.apache.org/jira/browse/KARAF-7096
             Project: Karaf
          Issue Type: Bug
            Reporter: Grzegorz Grzybek
            Assignee: Grzegorz Grzybek


It's a follow-up of the investigation from KARAF-6955. Copying the description:

I had problem after this change - {{jconsole}} stopped working and sample Java application ended with {{Connection refused}} exception.

I did enjoyable analysis and I found that:
* ports are opened on proper interfaces ({{::ffff:127.0.0.1}} in my case, which is an IPv6 address from _::ffff:0:0/96 CIDR_ that represents _Transition from IPv4_ address block)
* I could connect to RMI Registry at port 1099 and even obtain {{karaf-root}} object from there, which:
** is of {{javax.management.remote.rmi.RMIServer}} interface
** is of {{javax.management.remote.rmi.RMIServerImpl_Stub}} implementation

The problem is that this stub contains:
{noformat}
ref: java.rmi.server.RemoteRef  = {sun.rmi.server.UnicastRef2@1918} 
...
 ref: sun.rmi.transport.LiveRef  = {sun.rmi.transport.LiveRef@1925} "[endpoint:[192.168.0.38:44444](remote),objID:[2f23195f:178a6a29327:-7ffa, 4962682433218761153]]"
  ep: sun.rmi.transport.Endpoint  = {sun.rmi.transport.tcp.TCPEndpoint@1927} "[192.168.0.38:44444]"
   host: java.lang.String  = "192.168.0.38"
   port: int  = 44444 (0xAD9C)
{noformat}

The problem is that when {{RMIServerImpl_Stub}} is created *at server side* by karaf.management.server bundle, the bind address of this remote object is NOT taken from {{rmiServerHost}} property of {{org.apache.karaf.management}} PID. It's taken from (top to bottom):
* sun.rmi.transport.tcp.TCPEndpoint#getLocalEndpoint()
* java.net.InetAddress#getLocalHost()
* java.net.InetAddressImpl#getLocalHostName()
* java.net.InetAddress#getAddressesFromNameService()
* java.net.Inet6AddressImpl#lookupAllHostAddr()
* getaddress() libc method
* /etc/hosts

The way to solve this is to set {{java.rmi.server.hostname}} system property to 127.0.0.1, so the Stub contains proper address.



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