Description Markus Kuppe 2010-10-02 06:47:15 EDT

Based on a Skype discussion, the reasons for picking "localhost" are (+ == pro localhost, - == IP determined by /etc/hosts):

+ A service provider can overwrite the default with an ECF specific property upon service registration (org.eclipse.ecf.osgi.services.distribution.IDistributionConstants.SERVICE_EXPORTED_CONTAINER_FACTORY_ARGUMENTS)
- This sort of configuration should be determined dynamically. Either via system properties, configadmin or InetAddress.getLocalhost()... if they are strictly necessary in the first place. A service provider certainly does not want to make this decision/configuration during service registration. Especially since the arguments are RemoteServiceContainer specific and the currently active container is not known to the service provider during service registration.

+ InetAddress.getLocalhost().getHostName()/.getHostAddress is a non-reliable way to determine the public IP address
- It is the defined way to determine a host address/host name (in Java). It uses the system wide configuration which e.g. comes from /etc/hosts or DHCP. Why duplicate this kind of configuration into a (static) ECF specific property?

+ registering a service with the public IP address exposes a security risk
- Binding a RemoteServiceContainer to 0.0.0.0 instead of 127.0.0.1 is the security risk. Setting the service endpointId to "127.0.0.1" does not enhance security significantly as any skilled attacker will simple do a port scan.

+ production system need configuration anyway
- Administrators will usually set up /etc/hosts correctly or use dynamic means of configuration (DHCP)

+ dual homed devices need extra configuration
- This is not the default (yet) and thus KISS should be applied

So what are the possible implementations:

a) Do not register host containers automatically (see bug #303979 for counter arguments)
b) Create containers automatically, but by default only bind the RemoteServiceContainer to the loopback interface (while printing a warning/info). However, hostname(s) should not be hardcoded to "localhost" but determined dynamically:
b1) via InetAddress.getLocalhost().getHost*()
b2) System properties
b3) OSGi Configadmin
c) Create containers automatically and bind them to 0.0.0.0 (b1-3 apply here too).

Whatever we decide upon, behavior should be consistent across providers.