Re: how to debug dhcp?

David Timms wrote: > dragoran wrote: >> dragoran wrote: >>> John Reiser wrote: >>>>> when I try to use dhcp for my network device (eth0 - forcedeth) >>>>> it does >>>>> not get an IP with the result: failed >>>>> >>>> >>>> >>>>> 2) how can I debug it to find out what is causing it? >>>>> >>>> >>>> Boot single-user, invoke the dhcp program from a console in >>>> "non-daemon" >>>> mode, and watch. >>> how do I do this (found nothing in the man page) >>>> For dhcpd, consider flags -d -tf and perhaps -play. >>>> Also, consider running under strace. >>> I am talking about dhclient not dhcpd >>>> For lowest-level packet trouble, >>>> use a program such as tcpdump or ethereal to check what goes over >>>> the wire. >>>> >>>> >>> used ethreal an have not found anything that looks like an error... >>> >> >> this is what I get in /var/log/messages: >> Jul 19 09:08:39 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 6 >> Jul 19 09:08:45 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 9 >> Jul 19 09:08:54 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 10 >> Jul 19 09:09:04 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 12 >> Jul 19 09:09:16 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 19 >> Jul 19 09:09:35 chello062178124144 dhclient: DHCPDISCOVER on eth0 to >> 255.255.255.255 port 67 interval 5 >> Jul 19 09:09:40 chello062178124144 dhclient: No DHCPOFFERS received. >> >> wtf? >> who is broken here? should I fill a bug? > Can you run ethereal on the dhcp server {or a third machine} to > ensure the packets get to the server ? firewall stopping udp port 67 > or 68 at either end ? Slow negotiating switch or mismatched port > speeds ? > Is the DHCP server set to be authoritative; ? Without this I believe > win {for eg} tries hard to use any previous dhcp it last received, > not sure about fc-whatever. > At the server should see: > DHCP Discover -> server > client <- DHCP Offer > DHCP Request -> server > client <= DHCP ACK > > DaveT. > the problem is that I havn't any access to the server (its the ISPs dhcp server)