DHCP and Printers

Glenn Satchell Glenn.Satchell at uniq.com.au
Wed Dec 13 14:15:12 UTC 2006

>From: "Diego, Emil" <ediego at exchange.sba.miami.edu>
>Thanks for the quick response David & Simon.  Since it's both HP Jet
>Direct and Lanier printers that are giving me this problem I run with
>both solutions at once.  I'll start updating the bios on the HP Jet
>Direct printer and I will start analyzing the network packets between
>the DHCP and the Lanier printers.  
>The only thing is that I'm not too familiar with the data packets that
>DHCP uses to communicate.  Does anyone know of a good reference that
>shows the information layout of the packets? 


Use a smart packet snooper such as Ethereal (now known as Wireshark)
which decodes all the internal structures for you. http://www.wireshark.org/

There is a huge amount of detail on the packet structure in the rfc
documents in the doc subdirectory of the source distribution.

>-----Original Message-----
>From: dhcp-users-bounce at isc.org [mailto:dhcp-users-bounce at isc.org] On
>Behalf Of Simon Hobson
>Sent: Tuesday, December 12, 2006 3:01 PM
>To: dhcp-users at isc.org
>Subject: Re: DHCP and Printers
>Diego, Emil wrote:
>>I am running DHCP 3.0.5 on fedora core 4.  I have about 30 network 
>>printers ranging from HP JetDirect boxes to Lanier printers.  I have 
>>setup the DHCP server to assign an IP address to the printer, but I am 
>>running into a problem.  It seems that some of the printers never 
>>acknowledge the IP sent to them from the DHCP server and then tries to 
>>request the ip over and over again.
>>Here is some of the dhcp server log for the MAC address of one of my 
>>Dec 11 10:55:22 moya dhcpd: DHCPDISCOVER from 00:00:74:b2:53:64 via 
>>eth0 Dec 11 10:55:22 moya dhcpd: DHCPOFFER on to 
>>00:00:74:b2:53:64 via eth0 Dec 11 10:55:24 moya dhcpd: DHCPDISCOVER 
>>from 00:00:74:b2:53:64 via eth0 Dec 11 10:55:24 moya dhcpd: DHCPOFFER 
>>on to 00:00:74:b2:53:64 via eth0
>It's impossible to tell - if only you could look at the non existent
>logs in the printer and see what reason it gives :-(
>First thing would be to analyse the packets and see what options the
>printer requests - and make sure you supply everything it asks for. 
>Beyond that it's guesswork !
>I once had a printer (RIP attached to a Minolta copier) that didn't
>request the subnet mask, but even when I hard coded the options list for
>that device it still didn't accept a lease offer. It was a few years
>later (well after I'd given up and manually configured it) that I
>accidentally found a tech note that it won't accept a lease shorter than
>two years - yes TWO YEARS ! You have to wonder what some people are
>thinking ? Of all the things I'd considered, I'd never thought of that.

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