Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

[Revital Gorsht]

This is long overdue, but to close this thread: As of 7.3, global IP Routing is enabled and, by design, an AP will drop packets that are layer 2 broadcast and layer 3 unicast, as was the case with our DHCP offers since we had a broadcast address specified on the SVI. Once the "ip broadcast-address" statement was removed from the SVI, the AP was able to process the packet and receive an IP.  Hope this helps anyone else experiencing this issue...Thanks.-The EDUCAUSE Wireless Issues Constituent Group Listserv WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU wrote: -To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDUFrom: Jason Murray Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv Date: 10/19/2012 10:16AMSubject: Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCPOn 10/17/12 6:39 AM, Julian Y Koh wrote: On Oct 16, 2012, at 19:49 , Jason Murray jemur...@zweck.net wrote This is not completely related, but we just upgraded one of our Cisco routers, after the upgrade dhcp stopped working because one dhcp option was blank.  'Debug IP dhcp server' was the only way we would have noticed this problem. The router was silently discarding the replies. Can you share router model and software versions?The last time we had this problem, I documented it here:http://blog.zweck.net/2012/10/cisco-fails-to-relay-dhcp-requests.htmlWe have also seen this exact same problem on the Cisco 6509, although Idon't remember the exact software versions.-- Jason E. MurraySr. Systems EngineerWashington University in St. LouisPhone: 314-935-4865Email: jemur...@wustl.eduWeb: http://nss.wustl.edu/~jemurray/**Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.[attachment "signature.asc" removed by Revital Gorsht/fs/YorkU]**
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Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

[Jason Murray]

On 10/17/12 6:39 AM, Julian Y Koh wrote:
 On Oct 16, 2012, at 19:49 , Jason Murray jemur...@zweck.net wrote
 This is not completely related, but we just upgraded one of our Cisco 
 routers, after the upgrade dhcp stopped working because one dhcp option was 
 blank.'Debug IP dhcp server' was the only way we would have noticed this 
 problem.  The router was silently discarding the replies.

 Can you share router model and software versions?

The last time we had this problem, I documented it here:

http://blog.zweck.net/2012/10/cisco-fails-to-relay-dhcp-requests.html


We have also seen this exact same problem on the Cisco 6509, although I
don't remember the exact software versions.



-- 
Jason E. Murray
Sr. Systems Engineer
Washington University in St. Louis
Phone: 314-935-4865
Email: jemur...@wustl.edu
Web: http://nss.wustl.edu/~jemurray/


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Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

[Julian Y Koh]

On Oct 16, 2012, at 19:49 , Jason Murray jemur...@zweck.net wrote:
 
 This is not completely related, but we just upgraded one of our Cisco 
 routers, after the upgrade dhcp stopped working because one dhcp option was 
 blank.'Debug IP dhcp server' was the only way we would have noticed this 
 problem.  The router was silently discarding the replies.


Can you share router model and software versions?

-- 
Julian Y. Koh
Manager, Network Transport, Telecommunications and Network Services
Northwestern University Information Technology (NUIT)
2001 Sheridan Road #G-166
Evanston, IL 60208
847-467-5780
NUIT Web Site: http://www.it.northwestern.edu/
PGP Public Key:http://bt.ittns.northwestern.edu/julian/pgppubkey.html

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RE: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

[Case, Brandon J]

We had the exact same issue with our old WiSM1s after upgrading the 6500 they 
were in to 12.2(33)SXI. Apparently when the WiSMs first booted they sent DHCP 
requests with a blank hostname (although I think these were running something 
in the 5.2 train or perhaps earlier). 12.2(33)SXH didn't care and would process 
the request but SXI did care and would silently discard the requests. This was 
a huge issue for us because the WiSMs weren't getting addresses for their 
service ports and couldn't be configured remotely (no console server at that 
particular site at the time). Later versions of WiSM code seemed better and 
didn't send DHCP requests with a blank hostname.

As for the 3602s: we just installed a bunch of them and didn't have any issues 
with them getting DHCP leases. We're running ISC DHCP 3.1.3 and are using 6500s 
with the VS-S720-10G supervisor running 12.2(33)SXJ. I'd be happy to compare 
DHCP configs offline if it will help.

--
Brandon Case
Network Engineer, ITaP
Purdue University
ca...@purdue.edu
Office: (765) 49-67096
Mobile: (765) 421-6259
Fax:(765) 49-46620

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-Original Message-
From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
[mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Julian Y Koh
Sent: Wednesday, October 17, 2012 7:40 AM
To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
Subject: Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

On Oct 16, 2012, at 19:49 , Jason Murray jemur...@zweck.net wrote:
 
 This is not completely related, but we just upgraded one of our Cisco 
 routers, after the upgrade dhcp stopped working because one dhcp option was 
 blank.'Debug IP dhcp server' was the only way we would have noticed this 
 problem.  The router was silently discarding the replies.


Can you share router model and software versions?

-- 
Julian Y. Koh
Manager, Network Transport, Telecommunications and Network Services
Northwestern University Information Technology (NUIT)
2001 Sheridan Road #G-166
Evanston, IL 60208
847-467-5780
NUIT Web Site: http://www.it.northwestern.edu/
PGP Public Key:http://bt.ittns.northwestern.edu/julian/pgppubkey.html

**
Participation and subscription information for this EDUCAUSE Constituent Group 
discussion list can be found at http://www.educause.edu/groups/.

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Re: [WIRELESS-LAN] Cisco 7.3 Code and ISC DHCP

[Jason Murray]

This is not completely related, but we just upgraded one of our Cisco
routers, after the upgrade dhcp stopped working because one dhcp option was
blank.'Debug IP dhcp server' was the only way we would have noticed
this problem.  The router was silently discarding the replies.

...sent from my mobile device spelling and grammar my suffer...
On Oct 16, 2012 1:43 PM, Revital Gorsht revi...@yorku.ca wrote:

 Our most recent shipment of Cisco 3600 APs came with a preloaded 7.3 image
 and appear to be ignoring the DHCP offers being sent to them from our ISC
 DHCP server.  While spanning the port the AP is on, it is evident the
 offers are being sent from the DHCP server, yet the AP's debug messages
 insist its discovers are going unanswered.  Once the AP is configured with
 a static IP, it will then connect to the controller, running 7.2, and
 downgrade its image, at which point we clear the config (so the static IP
 is forgotten and the AP is forced to use DHCP) and the AP accepts the same
 DHCP offer without fail.

 Wondering if anyone else who has migrated to 7.3 code with CAP3602I's and
 using ISC DHCP is experiencing this, or if this is specific to our DHCP
 settings?  At the moment, I've got a case open with Cisco and am waiting on
 development to respond...

 Thanks.

 *
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