DHCP DISCOVER from cisco client (C1811W) goes unanswered
Duane Cox
duanec at mail.illicom.net
Wed Apr 4 16:18:59 UTC 2007
I have been fighting this one for a few weeks now. Something is wrong here
but I'm not sure what it is.
So a client gets this new cisco router, a C1811W, and sets it up for DHCP
and puts it on our network.
Or network is SUPPOSED to relay dhcp packets into the dhcp servers.
This problem became two fold.
At first I suspected it to be a problem with the relay agent (embedded
system). The DHCP packet enters one interface but doesn't come out the
other. So I brought the C1811W in-house in the lab to tear it apart.
Come to find out, not only does the relay agent not like this packet, but
the ISC DHCP server 3.0.5 doesn't either.
Investigating the log output during the arrival of the packet to the server
I get this notorious message:
"DHCPDISCOVER from 00:1b:0c:90:70:3e via eth0: peer holds all free leases"
uh? not that I can tell, what gives?
00:1b:0c:90:70:3e > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 618:
IP (tos 0x0, ttl 255, id 339, offset 0, flags [none], length: 604)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
00:1b:0c:90:70:3e, length: 576, xid:0x24d1, flags: [Broadcast] (0x8000)
Client Ethernet Address: 00:1b:0c:90:70:3e
Vendor-rfc1048:
DHCP:DISCOVER
MSZ:1152
CID:"cisco-001b.0c90.703e-Fa0"
HN:"Clarkip"
PR:SM+NS+DN+WNS+DG+SR+T150+VO
0x0000: 4500 025c 0153 0000 ff11 b83e 0000 0000 E..\.S.....>....
0x0010: ffff ffff 0044 0043 0248 d35a 0101 0600 .....D.C.H.Z....
0x0020: 0000 24d1 0000 8000 0000 0000 0000 0000 ..$.............
0x0030: 0000 0000 0000 0000 001b 0c90 703e 0000 ............p>..
0x0040: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0050: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0060: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0070: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0080: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0090: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00f0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0100: 0000 0000 0000 0000 6382 5363 3501 0139 ........c.Sc5..9
0x0110: 0204 803d 1900 6369 7363 6f2d 3030 3162 ...=..cisco-001b
0x0120: 2e30 6339 302e 3730 3365 2d46 6130 0c07 .0c90.703e-Fa0..
0x0130: 436c 6172 6b69 7037 0801 060f 2c03 2196 Clarkip7....,.!.
0x0140: 2bff 0000 0000 0000 0000 0000 0000 0000 +...............
0x0150: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0160: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0170: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0180: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0190: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01f0: 0000 0000 0000 0000 0000 0000 0000 0000 ...............
0x0200: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0210: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0220: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0230: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0240: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0250: 0000 0000 0000 0000 0000 0000 ............
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