option 82 logging error

[Marc Perea]

My packet capture shows using tethereal -V -i bge0:

Frame 11 (383 bytes on wire, 383 bytes captured)
    Arrival Time: Dec 11, 2008 12:04:49.118078000
<snip for brevity>
Bootstrap Protocol
    Message type: Boot Request (1)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 1
    Transaction ID: 0x5d5e057f
    Seconds elapsed: 0
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 0.0.0.0 (0.0.0.0)
    Next server IP address: 0.0.0.0 (0.0.0.0)
    Relay agent IP address: a.b.c.d (a.b.c.d)
    Client hardware address: 2a:22:15:47:f4:cd
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option 53: DHCP Message Type = DHCP Discover
    Option 60: Vendor class identifier = "uDHCP 0.9.6"
    Option 125: Unassigned (36 bytes)
    Option 55: Parameter Request List
        1 = Subnet Mask
        3 = Router
        6 = Domain Name Server
        12 = Host Name
        15 = Domain Name
        28 = Broadcast Address
    Option 82: Agent Information Option (36 bytes)
        Agent Circuit ID: 31302E34312E35302E3131363A312D34...
    End Option

Dec 11 12:04:49 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464946:49) larger than buffer.
Dec 11 12:04:49 isg-dhcp dhcpd: [ID 702911 daemon.error] DHCPDISCOVER from 2a:22:15:47:f4:cd via 74.207.128.1: network isg-test: no free leases

Is this not the correct option 82 format where it says 36 bytes are coming? Have I got an improperly configured L2DHCPRelay agent?

Marc Perea
Network Support Engineer
SRT Communications, Inc.
(701)858-5235
marccp at srttel.com


>>> Bruce Hudson <Bruce.Hudson at dal.ca> 12/11/2008 10:35 AM >>>
> 
>   if exists agent.circuit-id {
>       log(info, concat (
>		binary-to-ascii(10,8,".",leased-address),
>		" ASSIGNED TO AGENT.CIRCUIT-ID => "
>		,option agent.circuit-id)
>       ));
>   }
 
 
> Dec 11 08:34:15 isg-dhcp dhcpd: [ID 702911 daemon.error]
>    parse_option_buffer: option <unknown> (808464737:50) larger than buffer.

    I suspect your problem is some type of rogue device on your network
that is sending out "agent" options that are not encapsulated sub-option
spaces. When the server attempts to parse the "agent" option to see if the
"circuit-id" sub-option exists it finds a bogus sub-option number and a
length greater than the size of the "agent" option. The option number you
are getting (808464737) translates to "30303161" in hex or "001a" in
ASCII. 

    However, it is extremely odd that you are getting a 4-byte option
sub-option number. What version of the server are you running? According
to my 3.1.1 server:

		agent_universe.get_tag = getUChar;

This means you should only be seeing 1-byte option tags. 
--
Bruce A. Hudson				| Bruce.Hudson at Dal.CA 
UCIS, Networks and Systems		|
Dalhousie University			|
Halifax, Nova Scotia, Canada		| (902) 494-3405