question: private String lookupLocalAddress ( ) { long timeout = 120 * 1000L ; long expireTime = CurrentTime . currentTime ( ) + timeout ; String address ; while ( ( address = allocateLocalAddress ( ) ) == null && CurrentTime . currentTime ( ) < expireTime ) { try { Thread . sleep ( 1000 ) ; } catch ( Exception e ) { } } if ( address == null ) { throw new ConfigException ( L . l ( "Cannot find an internal local IP address for server {0}, external IP {1} within 120s." + " 'external-address=true' is used for cloud networks where the internal address is allocated dynamically." + " Check that the persistent address has been assigned in the cloud configuration or DNS." , _serverBartender . getId ( ) , _serverBartender . getAddress ( ) ) ) ; } return address ; }
target:  Looks up the local address when given an external address, e.g. for cloud systems that dynamically allocate local addresses.