TODOs, in random order:
=======================

- re-think the registration mechanism (mapping and decision criteria
  for in- and outgoing stuff...
  
- logging via syslog if running in daemon mode

- get_ip_by_host: reduce DNS timeouts

- Documentation

- automagically create a proper config file during install

- client authentication

- portability to other platforms / operating systems
  first goal: other Unixes