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DHCP Server Port-Based Address Allocation

I am having issues activating what is called the “DHCP Server Port-Based Address Allocation” feature on the new 3850 Model Cisco switch. This feature basically forces the DHCP server to handout a pre-assigned IP Address on a port basis.  Without this feature the DHCP will walk through its range when issuing an IP Address and you may end up with a different IP address each time the Cisco switch sees a  client plugged into the same port ( Cisco’s reference document, http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-sy/dhcp-15-sy-book/dhcp-prt-bsd-aa.pdf.)

 

Currently when issuing  a “reserved-only” (see page 7) command for the DHCP pool (pool1) that I created,  the DHCP server fail to issue any OFFER to the client. If I issue a “no-reserved-only” command the OFFERS comes out, but not with the pre-assigned address we want. For example, the client is issued a “192.168.1.1” IP address, not the “192.168.1.182” we pre-assigned.

 

Attached is the non-working reserved-only running-config, along with some show command

I've also attached,  the case for the one that connected (with not-pre-assigned address),once I issue the no-reserved command

Below is what the DHCP pool looks like:

Switch#show ip dhcp pool

Pool pool1 :

Utilization mark (high/low)    : 100 / 0

Subnet size (first/next)       : 0 / 0

 Total addresses                : 254

Leased addresses               : 0

Excluded addresses             : 3

Pending event                  : none

1 subnet is currently in the pool :

Current index        IP address range                    Leased/Excluded/Total

192.168.1.1          192.168.1.1      - 192.168.1.254     0     / 3     / 254 

 3 reserved addresses are currently in the pool:

Address          Client

192.168.1.189    Gi1/0/9

192.168.1.182    Gi1/0/2

192.168.1.192    Gi1/0/12

3 Replies 3

Hello

FYI -
I have tested this now on two different switch platforms and in both cases I obtain the same results that you have posted.

 

res

Paul


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Thanks for you reply Paul,

 

We did have  “DHCP Server Port-Based Address Allocation” feature working on an older 3750 Model Cisco switch.

 

Please advise; Does this appear to be due miss configuration? SW bug? Is there a workaround?

-Rafael

 

The SW version for the Model 3750 that worked

Cisco IOS Software, C3750 Software (C3750-IPBASEK9-M), Version 12.2(55)SE1, RELE
ASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Thu 02-Dec-10 07:46 by prod_rel_team
Image text-base: 0x01000000, data-base: 0x02D00000

The SW version for the Model 3850 that does not worked

Cisco IOS Software, IOS-XE Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIV

ERSALK9-M), Version 03.03.05SE RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2014 by Cisco Systems, Inc.

Compiled Thu 30-Oct-14 13:12 by prod_rel_team

 

 

Hello Rafael

Thats interesting - I tested this feature with upto-date Ios on both switches and couldnt get it working
WS-C3750G-48PS
WS-C3650-48TS

res
Paul


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul
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