Opened 12 years ago

Closed 12 years ago

#84 closed defect (fixed)

dhcp funny in attendee room

Reported by: Rob Austein <sra@…> Owned by: msackett@…
Priority: critical Milestone:
Component: network Keywords: dhcp
Cc: My Current Location:
My MAC Address: My OS:

Description (last modified by randy@…)

linksys bug
juniper bug
cisco bug

all worked around

Change history (7)

comment:1 Changed 12 years ago by msackett@…

Owner: changed from nweis@… to msackett@…
Priority: tbdmajor
Status: newaccepted
Type: requestdefect

comment:2 in reply to:  description Changed 12 years ago by msackett@…

Description: modified (diff)
Reporter: changed from randy@… to Rob Austein <sra@…>

Replying to

rob is clueful, has implemented dhcp in past, etc.

From: Rob Austein <sra@…>
Subject: ietf net seems not to like my wtr54gs?
To: randy@…
Date: Sun, 22 Mar 2009 00:52:26 -0700

not a big deal, but here's a weird one for you.

my little travel access point mysteriously stopped working. it was ok
the night i got here, when my room was still on hotel net. it does not
work now. am not sure but -think- it broke when my room was cut over
to ietf net yesterday.

"broke" appears to mean that it can't get a dhcp lease. if i plug it
into my laptop's wired ethernet with a crossover, i can see the dhcp
request go out, so it's not like it stopped asking or its public side
port broke or something. my laptop plugged into the room wired net
works fine. set back to factory defaults and reconfigured, several
times, no joy.

i don't have a good theory to explain this. least improbable theory
is that somebody configured dhcp server to refuse service when it sees
a request with the hostname wtr54gs, or something equally silly. can't
think why anybody would bother, but other theories seem even less
plausible (hardware broke in some way that doesn't show up with
crossover test? um, right).

usual disclaimers about own access point at meeting: beacon off, ssid
known only to me and friends, using only upstairs. ain't causing no
trouble, ain't doing no harm. but is it illegal?

comment:3 Changed 12 years ago by Hans Kuhn

9d:1e is the last part of Rob's mac address

comment:4 Changed 12 years ago by Hans Kuhn

Date: Sun, 22 Mar 2009 08:46:10 -0700
From: Randy Bush <randy@…>
To: IETF Meeting/NOC <trac@…>
Cc: msackett@…
Subject: Re: [IETF Meeting/NOC] #84: dhcp funny in attendeed room

linksys wtr54gs (sic -- wtr, not wrt)
mac address 00:18:39:39:9d:1e

comment:5 Changed 12 years ago by Hans Kuhn

Date: Sun, 22 Mar 2009 09:33:58 -0700
From: Rob Austein <sra@…>
To: trac@…
Cc: sra@…, msackett@…, Hans Kuhn
Subject: Re: [IETF Meeting/NOC] #84: dhcp funny in attendeed room

dump of a request packet from the wtr54gs (crossover cable, tcpdump,

Frame 1 (590 bytes on wire, 590 bytes captured)

Arrival Time: Mar 22, 2009 09:25:59.717089000
[Time delta from previous captured frame: 0.000000000 seconds]
[Time delta from previous displayed frame: 0.000000000 seconds]
[Time since reference or first frame: 0.000000000 seconds]
Frame Number: 1
Frame Length: 590 bytes
Capture Length: 590 bytes
[Frame is marked: False]
[Protocols in frame: eth:ip:udp:bootp]

Ethernet II, Src: Cisco-Li_39:9d:1f (00:18:39:39:9d:1f), Dst: Broadcast (ff:ff:ff:ff:ff:ff)

Destination: Broadcast (ff:ff:ff:ff:ff:ff)

Address: Broadcast (ff:ff:ff:ff:ff:ff)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)

Source: Cisco-Li_39:9d:1f (00:18:39:39:9d:1f)

Address: Cisco-Li_39:9d:1f (00:18:39:39:9d:1f)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)

Type: IP (0x0800)

Internet Protocol, Src: (, Dst: (

Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)

0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..0. = ECN-Capable Transport (ECT): 0
.... ...0 = ECN-CE: 0

Total Length: 576
Identification: 0x001f (31)
Flags: 0x00

0... = Reserved bit: Not set
.0.. = Don't fragment: Not set
..0. = More fragments: Not set

Fragment offset: 0

Time to live: 64

Protocol: UDP (0x11)
Header checksum: 0x788f [correct]

[Good: True]
[Bad : False]

Source: (
Destination: (

User Datagram Protocol, Src Port: bootpc (68), Dst Port: bootps (67)

Source port: bootpc (68)
Destination port: bootps (67)
Length: 556
Checksum: 0x564e [correct]

[Good Checksum: True]
[Bad Checksum: False]

Bootstrap Protocol

Message type: Boot Request (1)
Hardware type: Ethernet
Hardware address length: 6
Hops: 0
Transaction ID: 0x73060000
Seconds elapsed: 21510
Bootp flags: 0x0000 (Unicast)

0... .... .... .... = Broadcast flag: Unicast
.000 0000 0000 0000 = Reserved flags: 0x0000

Client IP address: (
Your (client) IP address: (
Next server IP address: (
Relay agent IP address: (
Client MAC address: Cisco-Li_39:9d:1f (00:18:39:39:9d:1f)
Server host name not given
Boot file name not given
Magic cookie: (OK)
Option: (t=53,l=1) DHCP Message Type = DHCP Discover

Option: (53) DHCP Message Type
Length: 1
Value: 01

Option: (t=57,l=2) Maximum DHCP Message Size = 576

Option: (57) Maximum DHCP Message Size
Length: 2
Value: 0240

Option: (t=61,l=7) Client identifier

Option: (61) Client identifier
Length: 7

Value: 01001839399D1F

Hardware type: Ethernet
Client MAC address: Cisco-Li_39:9d:1f (00:18:39:39:9d:1f)

Option: (t=12,l=8) Host Name = "WTR54GS"

Option: (12) Host Name
Length: 8
Value: 5754523534475300

Option: (t=55,l=10) Parameter Request List

Option: (55) Parameter Request List
Length: 10
Value: 010F03062C2E2F1F212B
1 = Subnet Mask
15 = Domain Name
3 = Router
6 = Domain Name Server
44 = NetBIOS over TCP/IP Name Server
46 = NetBIOS over TCP/IP Node Type
47 = NetBIOS over TCP/IP Scope
31 = Perform Router Discover
33 = Static Route
43 = Vendor-Specific Information

End Option

comment:6 Changed 12 years ago by randy@…

Priority: majorcritical

comment:7 Changed 12 years ago by randy@…

Description: modified (diff)
Resolution: fixed
Status: acceptedclosed
Summary: dhcp funny in attendeed roomdhcp funny in attendee room
Note: See TracTickets for help on using tickets.