KB ID 0001751

Problem

We have been asking for this for years! Even on my home network I’ve not been able to allocate an ASA DHCP reservation for my laptop and my MyCloud drive. I’ve been in discussions in forums with people who are convinced that putting a static ARP entry into the ASA would solve the problem (it doesn’t – I tested it extensively!)

But finally in version 9.13(1) we can now add a static DHCP reservation (MAC address to IP address).

Create an ASA DHCP Reservation

Assuming you have DHCP already setup e.g.

[box]

!
dhcpd address 10.254.254.10-10.254.254.75 inside
dhcpd enable inside
!

[/box]

Then simply add the reservation, you need to specify the MAC address as xxxx.xxxx.xxxx (that’s with full stops not colons), if in doubt, ping the existing IP address then execute a ‘show arp’ command to show you all the MAC addresses the firewall can see, so you can copy/paste it into the following command;

[box]

dhcpd reserve-address 10.254.254.50 38f9.d326.66cc inside

[/box]

Quite why it took so long for Cisco to give us this basic function, I have no idea.

Related Articles, References, Credits, or External Links

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