Hi,
we have inter-Cisco product issues. CAPWAP access points are not accepting the DHCP Offers from the SG300 switch. Potentially SG200 and all DHCP Servers of the Small Business line are affected.
Hi, Thank you for your answer conraddaniel. But, our issue was an error on the DHCP. The DHCP server pool for the APs was configured with lease time infinite (on a Cisco 6500). After capturing the packets and debugging on the AP we realized that the AP were receiving wrong values: DHCP: Scan: Renewal time: 2147483647 DHCP: Scan: Rebind time: 536870911 So, on the AP debugging we saw: DHCP: Scan: Renewal time larger than Rebind time On Cisco documentation: T1 Timer(Renewal) After a certain portion of the lease time has expired, you attempt to contact the server that initially granted the lease in order to renew the lease so its IP address can still be used. T2 Timer(Rebinding) If renewal with the original leasing server fails, because, for example, the server was taken offline, then you ideally try to rebind to any active DHCP server and try to extend its current lease with any server that allows it to do so. These T1 and T2 timers can be any values, but must be less than the IP address lease duration. T1 Timer must be less than T2. Generally T1 is set to 50 percent of the lease duration and T2 is set to 87.5 percent of the lease duration. Use this rule to set T1 and T2 timers. On the previous version of the WLC, the DHCP was configured in the same way and we confirmed that the APs received same times, but they ignored those wrong values. The workaround was to modify the lease time of the DHCP pool (1 day). This way, both timers had valid values and the APs accepted the DHCP OFFER. We still do not know why with lease infinite these timers have wrong values (a bug?).
+
*Mar 1 00:13:26.698: DHCP: Scan: Renewal time larger than Rebind time
IOS DHCP Client does not accept the DHCP Offer.
Here you can see that the Newal time (58) and Rebinding (59) is bigger and thus IOS rejects the Offer.
While testing with ISC-DHCP Server the options 58 and 59 are not present.
Paket is accepted.
That leaves 2 things:
- Bug that MUST be fixed
- Is there a workaround to remove the option 58 and 59? (Already tested: specify manual "DHCP Options" in Web+CLI explicitly forbidden to overwrite the current values. )
Cheers,
CK
