Exclude IP address from DHCP pool on ASA

[Dhaval Dikshit]

Hi,

I configured DHCP server on ASA 5505. Its working fine.

Now I want to exclude one IP address from configured DHCP pool.

Please guide me for same.

Thanks,

Dhaval Dikshit

[varrao]

Hi Dhaval,

The ASA does not have any exclude command as the IOS has, but what you can do is, exclude those IP addresses from the scope itself, like you have an ip range og 10.1.1.100-10.1.1.200, so if you need lets say first 10 ip's for teh servers, then you can define the range as:

dhcpd address 10.1.1.110 - 10.1.1.200

and firewall woudl not assign IP's from those 10.

Hope that helps

Thanks,

Varun

[ajay chauhan]

The only way to exclude address in DHCP on the ASA is to not include those address in the DHCP scope of addresses.

Thanks

Ajay

[david]

Good information.  Anyone know what will happen to "connected" users if the pool is changed?  For example, let's say I currently have users connected and using IP addresses 10.10.224.10, .11, 12, etc.  and then I change the pool to only allow 10.10.224.50 through 10.10.224.150.  Will the users be disconnected or will their session remain intact?  I need to change a pool, but don't want to disconnect current users.  Thanks!

[Jouni Forss]

Hi,

I checked this with changing my WLAN interfaces pool to something different than the current setting.

I couldnt see any problem with connectivity doing this. I imagine the host will probably get a new IP address eventually since the old binding will be cleared from the ASA:

I used a new command to enter the new desired pool without first removing the old one. Though I am not sure if this really matters compared to just removing the old pool and inserting a new one.

- Jouni