Prior to 4.2 we cannot exclude an ip address/range if the DHCP server is on IAP.
From 4.2 onwards, IAP local DHCP server will support exclude IP address/range.
With this feature we are supporting the following
A. exclude-address ip1 (excluding one IP address)
B. exclude-address ip1 ip2 (excluding range of ip address)
#show dhcp command will show the excluded ip address/range.