dhcp relay agent problem?

  • Thread starter Thread starter David Beaven
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David Beaven

Can anyone please explain why the client is not getting a lease using the
dhcp relay agent (hope this is the right forum for this)



Thanks

David



Client discover:



1026 99.687640 00304F1E1134 *BROADCAST DHCP Discover
(xid=74664FA6) 0.0.0.0 255.255.255.255 IP

DHCP: Discover (xid=74664FA6)

DHCP: Op Code (op) = 1 (0x1)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 0 (0x0)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 32576 (0x7F40)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 0.0.0.0

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 0.0.0.0

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP Discover

DHCP: Unrecognized Option = 116 (0x74)

DHCP: Client-identifier = (Type: 1) 00 30 4f 1e 11 34

DHCP: Host Name = CATS2550

DHCP: Client Class information = (Length: 8) 4d 53 46 54 20 35 2e 30

DHCP: Parameter Request List = (Length: 11) 01 0f 03 06 2c 2e 2f 1f
21 f9 2b

DHCP: End of this option field



DHCP Relay agent listening on 172.16.0.1 forwards to dhcp server
139.184.195.11



1028 99.687640 000BCD4E8CC3 00306E1D9438 DHCP Discover
(xid=74664FA6) 172.16.0.1 139.184.195.11 IP

IP: ID = 0x9711; Proto = UDP; Len: 328

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 328 (0x148)

IP: Identification = 38673 (0x9711)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 128 (0x80)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0xA7BE

IP: Source Address = 172.16.0.1

IP: Destination Address = 139.184.195.11

IP: Data: Number of data bytes remaining = 308 (0x0134)

DHCP: Discover (xid=74664FA6)

DHCP: Op Code (op) = 1 (0x1)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 1 (0x1)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 32576 (0x7F40)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 0.0.0.0

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 172.16.0.1

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP Discover

DHCP: Unrecognized Option = 116 (0x74)

DHCP: Client-identifier = (Type: 1) 00 30 4f 1e 11 34

DHCP: Host Name = CATS2550

DHCP: Client Class information = (Length: 8) 4d 53 46 54 20 35 2e 30

DHCP: Parameter Request List = (Length: 11) 01 0f 03 06 2c 2e 2f 1f
21 f9 2b

DHCP: End of this option field



Offer: client MAC 00:30:4f:1e:11:34 has reservation in dhcp server scope of
172.16.1.1



1029 99.689593 WATCHG040FD6 000BCD4E8CC3 DHCP Offer
(xid=74664FA6) 139.184.195.11 172.16.0.1 IP

IP: ID = 0x19D6; Proto = UDP; Len: 330

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 330 (0x14A)

IP: Identification = 6614 (0x19D6)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 127 (0x7F)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0x25F8

IP: Source Address = 139.184.195.11

IP: Destination Address = 172.16.0.1

IP: Data: Number of data bytes remaining = 310 (0x0136)

DHCP: Offer (xid=74664FA6)

DHCP: Op Code (op) = 2 (0x2)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 0 (0x0)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 0 (0x0)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 172.16.1.1

DHCP: Server IP Address (siaddr) = 139.184.195.11

DHCP: Relay IP Address (giaddr) = 172.16.0.1

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP Offer

DHCP: Subnet Mask = 255.255.0.0

DHCP: Renewal Time Value (T1) = 6:00:00

DHCP: Rebinding Time Value (T2) = 10:30:00

DHCP: IP Address Lease Time = 12:00:00

DHCP: Server Identifier = 139.184.195.11

DHCP: Domain Name = ids.ac.uk

DHCP: Router = 172.16.0.1

DHCP: Domain Name Server = 139.184.195.11 139.184.194.19

DHCP: End of this option field



Request: client says can I have the offer



1030 99.690570 00304F1E1134 *BROADCAST DHCP Request
(xid=74664FA6) 0.0.0.0 255.255.255.255 IP

IP: ID = 0x1FD; Proto = UDP; Len: 352

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 352 (0x160)

IP: Identification = 509 (0x1FD)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 128 (0x80)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0x3791

IP: Source Address = 0.0.0.0

IP: Destination Address = 255.255.255.255

IP: Data: Number of data bytes remaining = 332 (0x014C)

DHCP: Request (xid=74664FA6)

DHCP: Op Code (op) = 1 (0x1)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 0 (0x0)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 32576 (0x7F40)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 0.0.0.0

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 0.0.0.0

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP Request

DHCP: Client-identifier = (Type: 1) 00 30 4f 1e 11 34

DHCP: Requested Address = 172.16.1.1

DHCP: Server Identifier = 139.184.195.11

DHCP: Host Name = CATS2550

DHCP: Dynamic DNS updates = (Length: 24) 00 00 00 43 41 54 53 32
35 35 30 2e 61 64 2e 69 ...

DHCP: Client Class information = (Length: 8) 4d 53 46 54 20 35 2e 30

DHCP: Parameter Request List = (Length: 11) 01 0f 03 06 2c 2e 2f 1f
21 f9 2b

DHCP: End of this option field



DHCP relay agent forwards request:



1032 99.690570 000BCD4E8CC3 00306E1D9438 DHCP Request
(xid=74664FA6) 172.16.0.1 139.184.195.11 IP

IP: ID = 0x9714; Proto = UDP; Len: 352

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 352 (0x160)

IP: Identification = 38676 (0x9714)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 128 (0x80)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0xA7A3

IP: Source Address = 172.16.0.1

IP: Destination Address = 139.184.195.11

IP: Data: Number of data bytes remaining = 332 (0x014C)

DHCP: Request (xid=74664FA6)

DHCP: Op Code (op) = 1 (0x1)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 1 (0x1)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 32576 (0x7F40)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 0.0.0.0

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 172.16.0.1

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP Request

DHCP: Client-identifier = (Type: 1) 00 30 4f 1e 11 34

DHCP: Requested Address = 172.16.1.1

DHCP: Server Identifier = 139.184.195.11

DHCP: Host Name = CATS2550

DHCP: Dynamic DNS updates = (Length: 24) 00 00 00 43 41 54 53 32
35 35 30 2e 61 64 2e 69 ...

DHCP: Client Class information = (Length: 8) 4d 53 46 54 20 35 2e 30

DHCP: Parameter Request List = (Length: 11) 01 0f 03 06 2c 2e 2f 1f
21 f9 2b

DHCP: End of this option field



NACK. What is going on!



1033 99.691546 00306E1D9438 *BROADCAST DHCP NACK
(xid=74664FA6) 139.184.195.11 255.255.255.255 IP

IP: ID = 0x19D7; Proto = UDP; Len: 328

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 328 (0x148)

IP: Identification = 6615 (0x19D7)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 128 (0x80)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0xD10A

IP: Source Address = 139.184.195.11

IP: Destination Address = 255.255.255.255

IP: Data: Number of data bytes remaining = 308 (0x0134)

UDP: IP Multicast: Src Port: BOOTP Server, (67); Dst Port: BOOTP Client
(68); Length = 308 (0x134)

UDP: Source Port = BOOTP Server

UDP: Destination Port = BOOTP Client

UDP: Total length = 308 (0x134) bytes

UDP: UDP Checksum = 0x7D89

UDP: Data: Number of data bytes remaining = 300 (0x012C)

DHCP: NACK (xid=74664FA6)

DHCP: Op Code (op) = 2 (0x2)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 0 (0x0)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 0 (0x0)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 0.0.0.0

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 0.0.0.0

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP NACK

DHCP: Server Identifier = 139.184.195.11

DHCP: End of this option field



Then an ACK:



1034 99.693499 WATCHG040FD6 000BCD4E8CC3 DHCP ACK
(xid=74664FA6) 139.184.195.11 172.16.0.1 IP

IP: ID = 0x19D8; Proto = UDP; Len: 335

IP: Version = 4 (0x4)

IP: Header Length = 20 (0x14)

IP: Precedence = Routine

IP: Type of Service = Normal Service

IP: Total Length = 335 (0x14F)

IP: Identification = 6616 (0x19D8)

IP: Flags Summary = 0 (0x0)

IP: .......0 = Last fragment in datagram

IP: ......0. = May fragment datagram if necessary

IP: Fragment Offset = 0 (0x0) bytes

IP: Time to Live = 127 (0x7F)

IP: Protocol = UDP - User Datagram

IP: Checksum = 0x25F1

IP: Source Address = 139.184.195.11

IP: Destination Address = 172.16.0.1

IP: Data: Number of data bytes remaining = 315 (0x013B)

DHCP: ACK (xid=74664FA6)

DHCP: Op Code (op) = 2 (0x2)

DHCP: Hardware Type (htype) = 1 (0x1) 10Mb Ethernet

DHCP: Hardware Address Length (hlen) = 6 (0x6)

DHCP: Hops (hops) = 0 (0x0)

DHCP: Transaction ID (xid) = 1952862118 (0x74664FA6)

DHCP: Seconds (secs) = 0 (0x0)

DHCP: Flags (flags) = 0 (0x0)

DHCP: 0............... = No Broadcast

DHCP: Client IP Address (ciaddr) = 0.0.0.0

DHCP: Your IP Address (yiaddr) = 172.16.1.1

DHCP: Server IP Address (siaddr) = 0.0.0.0

DHCP: Relay IP Address (giaddr) = 172.16.0.1

DHCP: Client Ethernet Address (chaddr) = 00304F1E1134

DHCP: Server Host Name (sname) = <Blank>

DHCP: Boot File Name (file) = <Blank>

DHCP: Magic Cookie = 99.130.83.99

DHCP: Option Field (options)

DHCP: DHCP Message Type = DHCP ACK

DHCP: Renewal Time Value (T1) = 6:00:00

DHCP: Rebinding Time Value (T2) = 10:30:00

DHCP: IP Address Lease Time = 12:00:00

DHCP: Server Identifier = 139.184.195.11

DHCP: Subnet Mask = 255.255.0.0

DHCP: Dynamic DNS updates = (Length: 3) 00 ff 00

DHCP: Domain Name = ids.ac.uk

DHCP: Router = 172.16.0.1

DHCP: Domain Name Server = 139.184.195.11 139.184.194.19

DHCP: End of this option field
 
General reasons:

1) DHCP Relay is not configured to reach the proper DHCP server
2) Routing problems between DHCP Relay and DHCP Server
3) DHCP server has no scope for the segment/subnet or scope is not
activated
4) Scope is exhausted (no available addresses)
6) DHCP server is not running
7) DHCP server is not authorized
8) Client is not set to obtain an IP address automatically
(not a DHCP client)
9) Some other machine is using the clients "reserved" or
assigned IP address

I think that is all of them.

Note that if you are using a reservation there could be a mismatch
between the client's actual NIC address and the configuration on
the reservation settings.
 
Surely the netmon info means that it can't be 1, 2, 3, 4, 6, 7, 8 and the
mac address matches that given out in the offer. Not sure how 9 could
happen (it isn't the client declining the Ip address)
Any more thoughts?
Thanks
David
 
No it is isn't switched
ipconfig /renew doesn't help.
I will try and increase logging levels on the dhcp server (?from the dhcp
snapin - haven't looked yet)
David
 
You still have not described the precise setup and
symptoms, perhaps one of use can find something
you have overlooked in 1-8 (I renumbered by adding
one and apparently let out position 5. <grin>)

#9 would occur if the client decided to forego the
IP due to duplicate address detected.

What does IPConfig /all on the client show?

Oh, and the obvious -- #5 <grin> Client and
DHCP are not actually on the same segment/broadcast
domain? (Most likely if a VLAN switch is involved...)

After that we only have #10 -- a bug.

--
Herb Martin

David Beaven said:
Surely the netmon info means that it can't be 1, 2, 3, 4, 6, 7, 8 and the
mac address matches that given out in the offer. Not sure how 9 could
happen (it isn't the client declining the Ip address)
Any more thoughts?
Thanks
David
 
And #11 is that superscope wasn't defined (which is what the problem was)

Not sure why superscopes are truely necessary - seems like a programme
coding grammar issue??

David


Herb Martin said:
You still have not described the precise setup and
symptoms, perhaps one of use can find something
you have overlooked in 1-8 (I renumbered by adding
one and apparently let out position 5. <grin>)

#9 would occur if the client decided to forego the
IP due to duplicate address detected.

What does IPConfig /all on the client show?

Oh, and the obvious -- #5 <grin> Client and
DHCP are not actually on the same segment/broadcast
domain? (Most likely if a VLAN switch is involved...)

After that we only have #10 -- a bug.
 
And #11 is that superscope wasn't defined (which is what the problem was)
Not sure why superscopes are truely necessary - seems like a programme
coding grammar issue??

Superscopes are only needed for "multinets" -- more than one
logical subnet on a single segment.
 
Checkout these links for more information about superscopes:
161571 Using DHCP "Superscopes" to Serve Multiple Logical Subnets
http://support.microsoft.com/?id=161571

186341 Superscoping vs. Supernetting
http://support.microsoft.com/?id=186341

255999 Increasing the Number of IP Addresses on a Subnet
http://support.microsoft.com/?id=255999
----
Thanks,
Rakesh Chanana [MSFT]

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