09-21-2014 10:41 PM
My VLANs terminate at my switches, so I use DHCP relay with Option82 to hand out addresses for the VLAN subnet. After upgrading from 1.3.7.18 to 1.4.0.88, DHCP isn't being handed out on my VLANs. Anyone else having this problem?
Solved! Go to Solution.
10-12-2014 11:31 AM
Confirmed... I'm seeing the exact same behavior! Nice find.
Here are two packet captures from the SG300 to my DHCP server:
1.4: https://www.cloudshark.org/captures/f74bcfad752c
1.3: https://www.cloudshark.org/captures/76360f902726
10-14-2014 04:10 AM
Hi,
Yes, it does change but no issue with Windows 2008 server.
What is your DHCP server?
Regards,
Aleksandra
10-14-2014 07:40 AM
Dnsmasq version 2.68
10-15-2014 12:16 AM
Hi,
Have you seen this working before with any other DHCP relay agents?
Aleksandra
10-15-2014 08:08 AM
Yes. dnsmasq is incredibly prolific, it's used in nearly every open source router.
10-16-2014 12:21 AM
No doubt about this. Just there is a small difference between relay and regular DHCP discovery/request.
10-16-2014 08:13 AM
If you want to try to reproduce, Download a distribution that includes dnsmasq as it's DHCP server or just run Ubuntu from a live USB.
If there are other packet captures or anything else I can do on my network to give you information, I'm more than willing to help. I want to keep my firmware current but at this rate we'll be stuck on 1.3 forever.
10-16-2014 09:18 AM
Hi Jonathan,
I guess it would be good idea to open an official ticket with Small Business Support team so we will document everything in details:
http://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html
Regards,
Aleksandra
11-03-2014 01:19 AM
Hello All,
It's the same for me here. DHCP was working before upgrade but not after.
Windows clients can obtain IP on the vlan but wyses clients and windws CE clients fail to have IP via DHCP relay.
11-03-2014 02:45 AM
Hi,
Have not seen such an issue yet but if there is a problem with latest firmware I strongly recommend you to open ticket with Small Business team so they can narrow down and if needed open bug:
http://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html
Regards,
Aleksandra
11-04-2014 03:14 AM
I've no open contrat for our SMB switch so no support...
May be I've found a workaround for this issue. After many many try this issue seams to not be a DHCP relay issue but a global routing break that cause DHCP relay very very slow and cause timeout for some DHCP clients (in my case Wyse ThinOS).
The solution for me was to increase TCAM routing ressource from 128 to higher value.
We upgrade from firmware 1.0 to 1.4 and I belive that TCAM partitioning was quite different.
11-04-2014 03:14 AM
That's why I could not reproduce the issue in test or mock-up pre-update systems.
Could you confirm that:
-Is it normal to have, for each host routed via SG300, 1 Neighbors TCAM entry? So Sg300 limit routing to -+400 hosts dependent of ACL / Services and routing interface in configuration.
-Do you have TCAM count of new Sg500?
Many thanks in advance.
11-12-2014 05:00 AM
I reply to my previous post: as I can find on internet SG500X device is 3072 TCAM entries and the Sx500 device is 2048.
11-04-2014 09:49 AM
Is there a log entry or anything that would indicate it has ran out of TCAM resources?
11-06-2014 02:10 AM
We have theses log entry :
Error %ARP-E-ARPTBL: ARP Table Overflow, aggregated (3)
Error %ARP-E-ARPTBL: ARP Table Overflow
Error %ARP-E-ARPTBL: ARP Table Overflow, aggregated (9)
Error %ARP-E-ARPTBL: ARP Table Overflow
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