dhclient dead

[gusti <ggh.develop@gmail.com>]

Hello

I'm using debian stable and kernel 2.6.18-5-686, and after some minutes 
I lost the network connection.
I'm using the binary 'dhclient', see below, any ideas about the problem. 

Thank you in advance,
    Gustavo

 pr100:/root# dhclient -e eth1
 Internet Software Consortium DHCP Client 2.0pl5
 Copyright 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.
 All rights reserved.

 Please contribute if you find this software useful.
 For info, please visit http://www.isc.org/dhcp-contrib.html

 sit0: unknown hardware address type 776
 sit0: unknown hardware address type 776
 Listening on LPF/eth1/00:04:23:50:dd:5b
 Sending on   LPF/eth1/00:04:23:50:dd:5b
 Sending on   Socket/fallback/fallback-net
 DHCPREQUEST on eth1 to 255.255.255.255 port 67
 DHCPACK from 192.168.1.1
 SIOCADDRT: File exists
 bound to 192.168.1.2 -- renewal in 20984 seconds.