DHCP Server not responding to specific client

[tuaris]

After apply the upgrade to the 24.7 series from 24.1, the DHCP service is refusing to assign an IP address to some clients.  I'm not sure how to troubleshoot this.  There are no entries in the logs.

UPDATE:

Looks like it's more than one client.  Some get a response, other's do not.

[EricPerl]

In the log view, did you change the log level?
At Information level, you see a brief summary of the messages received and sent.

[planetf1]

* You could inspect network traffic with wireshark or similar?
* Any firewall rules blocking traffic?
* Is vlan configuration correct?
* Any managed switches involved?