If you are using openvpn, and have a windows XP as Client, and have some troubles with dhcpclient

Mon Aug 01 11:34:29 2005 Route: Waiting for TUN/TAP interface to come up…
Mon Aug 01 11:34:30 2005 TEST ROUTES: 0/0 succeeded len=-1 ret=0 a=0 u/d=down
Mon Aug 01 11:34:30 2005 Route: Waiting for TUN/TAP interface to come up…
Mon Aug 01 11:34:31 2005 TEST ROUTES: 0/0 succeeded len=-1 ret=0 a=0 u/d=down
Mon Aug 01 11:34:31 2005 Initialization Sequence Completed With Errors (see http://openvpn.net/faq.html#dhcpclientserv )

Please try this fix:
Go to properties of you tap-adapter, go to avanced, then go to Media Status, put that on allways connected.