how to debug NetworkManager ?

[Michal Jaegermann]

On Tue, Oct 12, 2010 at 12:58:42PM +0300, cornel panceac wrote:
> 
> but, the route was still not set, so i had to run as usual
> 
> dhclient eth0
> 
> so that i can talk with the internet again.

NetworkManager is presumably running that for you if you have
an interface configured with a 'dhcp' prototype so either the first
response is incomplete, or there is a timeout somewhere, or there is
something not expected in an interface configuration, or ...
You may try to trace 'nmcli'.  Maybe this will give you a better
insight what is happening.  Do you have a default route already
configured elsewhere?  BTW - 'man nmcli' has some information.

> what means "Require ipv4 addressing
> for this connection to complete" ?"

Sounds like you are bringing this interface as IPv6 only for some
reasons while the other side wants to see IPv4.  Just a guess ...

   Michal