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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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Message from jemurray@zweck.net

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" <revital@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.



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

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

On Oct 16, 2012, at 19:49 , Jason Murray 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: PGP Public Key: ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Message from caseb@purdue.edu

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 caseb@purdue.edu Office: (765) 49-67096 Mobile: (765) 421-6259 Fax: (765) 49-46620 PGP Fingerprint: 99CB 02D6 983C 1E2A 015F 205C C7AA E985 A11A 1251
Message from jemurray@zweck.net

We are looking to upgrade from 2008 to 2012 for the newer features over the next couple of weeks. Also with 2012 R2 it looks like there are a number of enhancements to the existing IPAM functionality in 2012.

 

 


~Patrick

 

 

 

Patrick Goggins

Senior Systems Administrator

University of Wisconsin - Green Bay

 

 

 

I think I saw that there are now WMI calls to poll DHCP status from the 2012 servers as well, so you can integrate into monitoring software.

 

Dan Scherck

The Evergreen State College

 

Whose “best practice”?  Just reading this thread tells me there either is no agreement or, if anything, it’s slanted to ISC.  I think “best practice” probably means “we don’t know linux/unix”.

 

Having said that, we’re also being pushed to move from our (rock solid) ISC to Microsoft so …

People using MS, what kind of logs can you generate?  Specifically, can you search for lease information from the CLI? Also, do you have CLI ability for adds/modifications/deletions of records (scopes)?

 

Thanks,

Brian

 

Brian,

 

Get-DhcpServerv4Lease works for real-time querying of scope of individual scopes. Historical would require parsing the log file manually, depending on how much you need to go back and if it’s more than 7 days a script to parse the log file from the day before and loading into a database might be needed. DHCP reservations can be done through the Add-DhcpServerv4Reservation command (there is a IPv6 version of the command as well), they can also be modified and deleted as well.

 

With regards to a web interface, I don’t know of anyone with anything existing out there. However, the same options should be exposed via the .NET framework for custom web-based queries say if you were looking for a specific hostname or MAC address in real-time. Historical would require some sort of database on the backend with the daily logs loaded in for historical tracking.

 

 

~Patrick

 

The web interfacing is something we’ve built.  As long as I have CLI ability to manipulate the DHCP record (server) and DHCP log I can migrate.  Of course, I’ll have to put cat, grep and awk on the Windows box so it acts somewhat like a production system rather than a toy ;)

 

Thanks for the info.  I’ll check out those commands!

 

-Brian

 

Jeff,

 

At the risk of starting a religious war..

 

But Windows is so much easier to work with, so it must be better, right?

 

Honestly, I’m in the “if it aint broke..” camp.  And Windows logging, at least up to 2003 (I have limited experience with 2008) is pathetic.  Patrick Goggins did send some CLI (if I understand his response) commands that I’ll take a closer look at.  But really, for speed, ease of use, flexibility and stability, I’d much prefer to stick with ISC.  Unfortunately, my 30 years of experience don’t mean much against the Microsoft Marketing Machine.

 

.. I find myself using cat, grep and awk on my Windows systems more and more though.

 

-Brian

 

There are PowerShell equivalents to those commands as well.

 

cat = Get-Content (there is also an alias so you can just run cat)

grep = Select-String

awk = there are built-in commands regex methods (also, the full .NET stack is available so if you wanted to do any integration with AD, it’s there)

 

Both ISC and Windows work and can be automated. The real questions are with your environments as to which platform(s) is/are the staff familiar with? Does the platform work with our backup software? How much care and feeding does it require? Can it really do what we want it to do? How hard is to hire for someone with X or Y skills?

 

 

 

~Patrick

 

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