Cisco dhcp with reserved only-address issues.

[dbudzowski2]

I have master Cisco ASR1002-X router with dhcp server.

I have 120 Cisco small client routers with dynamic ip dhcp addresses.

All dhcp leases are made by reserved-only IP address with client-id.

When the small client router is restarted sometimes the same client router is identified by:

client-id: 018c.1e80.3b08.00

or

client-id: 0063.6973.636f.2d38.6331.652e.3830.3362.2e30.3830.302d.4769.302f.302f.30 (ascii cisco-8c1e.803b.0800-Gi0/0/0).

Why is that happeing? How to make full static dhcp reserve only address?

[MHM Cisco World]

small client router which model ?

MHM

[dbudzowski2]

Cisco c1121-4pltep

[Elliot Dierksen]

I have had better luck using the "hardware-address" to identify the client as opposed to "client-id". I have done what you describe before. You exclude the entire network using "ip dhcp excluded-address", and then create an "ip dhcp pool" for each reserved client. You can do this using a file on the flash that preserves the lease information, but that is a little more complicated IMHO. I prefer the pool per client method.

[dbudzowski2]

Unfortunately hardware-address doesn`t work on Cisco ASR 1002-X as dhcp server. Please show me part of your config.

My code looks like this:

Spoiler

ip dhcp pool 194.61.0.0/26
network 194.61.0.0 255.255.255.192
default-router 194.61.0.1
dns-server 194.247.62.6 194.247.62.18
lease 0 1
reserved-only
address 194.61.0.2 client-id 0100.b771.e82d.a2
address 194.61.0.3 client-id 01e0.5fb9.b8b0.84
address 194.61.0.6 client-id 0170.ca9b.9919.56
address 194.61.0.7 client-id 01c8.9c1d.ea29.08
address 194.61.0.10 client-id 017c.310e.ed82.00
address 194.61.0.11 client-id 01bc.4a56.01db.8a
address 194.61.0.12 client-id 0063.6973.636f.2d31.3066.392e.3230.3133.2e39.6135.392d.4769.302f.302f.30
address 194.61.0.13 client-id 0063.6973.636f.2d36.6362.322e.6165.6138.2e33.3536.312d.4769.302f.302f.30

[MHM Cisco World]

In client router try config client-id by

Ip dhcp client client-id interface or hex

MHM

[Elliot Dierksen]

It has been a long time since I had to do this, and I have never done it in an ASR. The key piece in this is you have to do a unique pool for each client. You can make that less painful by using inheritance. I am cobbling this together from several customer configs, so your mileage may vary.

ip dhcp pool PARENT-66
   network 10.66.0.0 255.255.0.0
   domain-name company.com
   dns-server 192.168.232.227 192.168.232.126 192.168.232.225
!
ip dhcp pool CLIENT-1
   network 10.66.1.0 255.255.255.0
   default-router 10.66.1.1
!
ip dhcp pool 00110AF64E9C
   host 10.66.1.53 255.255.255.0
   hardware-address 0011.0af6.4e9c ieee802
!