0000637: pfdhcplistener: option 82 wrong values - PacketFence

Notes
(0001167) user4 2009-03-23 19:58	Even the fact that port=0/14 is written shouldn't be this way ... the port field should simply contain the ifIndex of the switchport

(0001351) obilodeau (reporter) 2009-10-21 13:02	Hi maikel, We lost track of the signification of enabling option 82 (dhcpoption82logger=enabled). Why would someone want that? We experienced a condition where a host in registration would update its node entry to set a wrong vlan with this option turned on. We are thinking of fixing it or removing it entirely but would like to know to who it is useful and in what context.

(0001639) obilodeau (reporter) 2010-09-08 11:40	Hi maikel, Is this switch a Cisco 3550? Because these are known to have ifIndex be similar to ports # but off by one or more.

(0001691) mattgriffiths (reporter) 2010-09-24 02:59	Hi, I've been developing a use case for Packetfence within a company in a completely passive mode where we're using the dhcp fingerprinting feature to build a database of classified mac addresses for unmanaged (non dot1x) assets. We add a dhcp helper everywhere pointing at pf and publish aspects of the node table into an ldap directory for use by Cisco ACS RADIUS server host lookup requests. In this context where we're not even telling pf about the network switches it's very useful to have the switch port information in the node table from option 82 when we're in a discovery mode before implementing dot1x on a site. We also have sites with switches that don't support option 82 insertion - to help us know where a mac is coming from I've added a giaddr (router ip) column to the node table and modified pfdhcplistener to insert the giaddr from the dhcp packet. I've tested option 82 with various Cisco 3560 and 3750 switches and don't have the results to hand but found that the switch port recorded by pf was out by 4 on models with 4 sfp slots and out by 2 on models with 2 sfp slots. The switch info from option 82 in the node table (even with wrong ports) is still useful in my discovery context. Regards Matt

(0001695) obilodeau (reporter) 2010-09-27 12:14	I'm glad that we have a trace of why is option 82 useful. Thanks for that! :) I'm pretty sure that the off by 2, 4 is not something we could easily avoid because we are showing what the switch sent us. However, the ifIndex could be translated to dot1d port or better to be more meaningful. See 0001054 for an example of what I mean.

(0001696) obilodeau (reporter) 2010-09-27 12:23	I'm closing this. Re-open if: - you see reproducible event of 0/<port> being sent instead of ifIndexes - ifIndex not properly recorded Don't re-open if: - you see off-by one reports where the ifIndex and dot1d elements of the switch don't agree (presence of SFP ports or weird switch ifIndex indexing) In these cases, an updated node lookup with per-switch translation will be implemented in: 0001054

Issue History
Date Modified	Username	Field	Change
2009-03-23 11:10	maikel	New Issue
2009-03-23 19:57	user4	Status	new => assigned
2009-03-23 19:57	user4	Assigned To	=> user4
2009-03-23 19:58	user4	Note Added: 0001167
2009-04-13 13:33	user4	Category	1.8.0 => 1.8.3
2009-06-05 08:55	user4	Category	1.8.3 => 1.8.4
2009-07-16 17:21	obilodeau	Category	1.8.4 => 1.8.5
2009-10-21 13:02	obilodeau	Note Added: 0001351
2009-10-21 13:02	obilodeau	Assigned To	user4 =>
2009-10-21 13:02	obilodeau	Category	1.8.5 => future
2010-09-08 11:40	obilodeau	Note Added: 0001639
2010-09-08 11:40	obilodeau	Status	assigned => feedback
2010-09-08 11:40	obilodeau	Category	future => dhcp
2010-09-08 11:40	obilodeau	Product Version	trunk => 1.8.1
2010-09-08 11:40	obilodeau	Summary	pfdhcplistener => pfdhcplistener: option 82 wrong values
2010-09-24 02:59	mattgriffiths	Note Added: 0001691
2010-09-27 12:14	obilodeau	Note Added: 0001695
2010-09-27 12:23	obilodeau	Note Added: 0001696
2010-09-27 12:23	obilodeau	Status	feedback => resolved
2010-09-27 12:23	obilodeau	Resolution	open => no change required
2010-09-27 12:23	obilodeau	Assigned To	=> obilodeau
2011-05-04 11:51	obilodeau	Status	resolved => closed

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