Hey im not a firewall engineer but just seen this
There is no support for DHCP-reservation on the ASA. As shown the are "workarounds" (aka dirty tricks) but IMO it's not worth going that way. The focus of DHCP on the ASA is more or less for the home-office but it's not meant to be a fully featured DHCP-server.
This feature is now supported on ASA in version 9.13(1) and later
Magnus-5506-Desk# sh run dhcpd
dhcpd dns 192.168.1.22
dhcpd domain cisco.com
dhcpd option 4 ip 172.18.124.1
dhcpd address 192.168.100.100-192.168.100.200 inside
dhcpd enable inside
dhcpd reserve-address 192.168.100.199 ecb5.fa0f.988b inside
@Jay Johnston that's interesting. I don't see reference to that new feature in the release notes.
It doesn't even seem to be in the command reference!
I was about to ask the same thing!
Release notes do not mention this new feature... I'm looking at replacing an aging ASA5505+2911 Branch Router with a single FirePower 1010 which runs ASA 9.13(1) and this dhcpd reserve-address feature would be really really useful because that's one of the things the 2911 does which the ASA never could.
Can you update this thread when you've got the documentation updated?