DHCP over PPPoE

[JOBY THAMPAN]

-----Original Message-----
From: dhcp-users-bounce at isc.org [mailto:dhcp-users-bounce at isc.org]On
Behalf Of Glenn Satchell
Sent: Thursday, April 27, 2006 6:12 PM
To: dhcp-users at isc.org
Subject: Re: DHCP over PPPoE



>From: JOBY THAMPAN <JOBYTHAMPAN at nestec.net>
>To: "'dhcp-users at isc.org'" <dhcp-users at isc.org>
>Cc: "'Glenn.Satchell at uniq.com.au'" <Glenn.Satchell at uniq.com.au>
>Subject: DHCP over PPPoE
>Date: Thu, 27 Apr 2006 14:19:35 +0530
>
>> Hi all ,
>> 
>> 	I have a setup like this
>> 	
>> 	Linux Machine 1
>> 	Eth0	-	DHCP Server
>> 
>> 
>> 	Linux Machine 2
>> 	Eth1	-	Got IP from DHCP Server
>> 	Eth0	-	PPPoE Server 
>> 	ppp0 Interface formed
>> 
>> 
>> 	Linux Machine 3
>> 	Eth0	-	PPPoE Client
>> 	Eth1	-	IP is 192.168.40.1
>> 	ppp0 Interface formed
>> 	Dhcp Relay is running on Linux Machine 3
>> 
>> 
>> 	Windows Machine 4
>> 	Expecting an IP of 192.168.40. after renewing the ip address of
>> windows machine
>> 
>> 	But there is no result
>> 	
>> 	Without PPPoE interfaces the windows machine is getting an ip in the
>> range 192.168.40.
>> 	
>> 	Wouldn't DHCP Protocol work over PPP Interface?
>> 
>> 	If any one knows, please reply.
>> 
>> Rgds
>> Joby

So the dhcrelay is forwarding the requests across the PPPOE link. That
should work, but maybe it isn't hearing the responses from the dhcp
server because the dhcrelay isn't listening on the ppp0 interface?

When you start dhcrelay which interfaces does it say it is listening
on? I bet ppp0 is not on that list. Listening on eth0 is no good as
dhcrelay doesn't know how to unencapsulate the ppp packets.

Perhaps running a packet sniffer on the ppp0 interface might show you
what traffic is there?

An alternative might be to run dhcrelay on a different linux box on the
192.168.40 subnet (if there is one). It doesn't have to run on the
gateway device.

regards,
-glenn


Hi,	
	that was right, it was not listening on ppp0 interface 
	But after making it listen on ppp0 Interface by giving dhcrelay -i
ppp0 -i eth1 -i eth0 <server ip>

	I tried with sniffer but still the DHCP Offer packet is reaching
only upto ppp0 i/f, it is not seen at the windows machine.
	windows mach connected with eth1 of Linux Mach 2 (I didn't mentioned
earlier).

	My basic aim to test it is to make sure whether dhcp relay work over
ppp interface.


Rgds
Joby


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