Cisco Catalyst 9500-24Q ip helper-address problem

[eliemehawej]

Dears, 

I have a Cisco Cat 9500-24Q acting as Core Switch running the latest version 16.8.1a.

Under its SVIs interfaces, the command "ip helper-address x.x.x.x" pointing to an external DHCP server.

Users are being delayed to acquire a DHCP address from the external DHCP server (around 10-15 minutes).

Note that Users withing the same VLAN of the DHCP server are normally acquiring IP address.

Any idea on the above.

Thank you,

[tlr]

We were also hit by this bug on 16.9.3 and C9500-40X.

Upgraded to 16.9.4 and ip-helper worked again.

/tobias

[uhabbe]

Hi Tobias,

thank you for this information. The bug description lists 16.12(1.10) as the only "known fixed", version which I could not find in the download area on cco.

[Jaderson Pessoa]

Could you share your simple topology about your environment?
Is it a windows dhcp? Linux? Locally on L3?
It is possible to share information about your configuration?

it is possible to copy the output below.

show running-config

debug ip dhcp server packets