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New Member

Router not releasing DHCP addresses, can I clear?

I am using a Cisco 877, but I have noticed I get a new IP everytime, but the next one up, there are only 2 PC's on this router. I get an IP of 192.168.2.11, then tomorrow it will be 192.168.2.12, then 13, 14 etc, surely it should release the IP after a day or 2 and reuse the IP's at the beggining of the scope?

ip dhcp pool client

import all

network 192.168.2.0 255.255.255.0

default-router 192.168.2.100

dns-server 87.86.18.1 90.20.23.9 190.72.0.9

lease 0 2

7 REPLIES
Bronze

Re: Router not releasing DHCP addresses, can I clear?

Are you by any chance having filters on the interface?

I've seen this behavior before when applying an access-list to the interface of the DHCP clients.

New Member

Re: Router not releasing DHCP addresses, can I clear?

Yeah I do, here is the config. It's a 837 not a 877, sorry about that.

New Member

Re: Router not releasing DHCP addresses, can I clear?

Just cleared the arp, but my pc wants to continue to now have 192.168.2.20, why not 192.168.2.11 or 12 (the start of the DHCP scope)?

Hall of Fame Super Gold

Re: Router not releasing DHCP addresses, can I clear?

Actually I believe the IOS DHCP server will use linearly the pool unless the client requests an available address.

Do "show ip dhcp pool" to see which address will be handed out at the next request .

New Member

Re: Router not releasing DHCP addresses, can I clear?

Here it is:

H0m3#sh ip dhcp pool

Pool client :

Utilization mark (high/low) : 100 / 0

Subnet size (first/next) : 0 / 0

Total addresses : 254

Leased addresses : 1

Pending event : none

1 subnet is currently in the pool :

Current index IP address range Leased addresses

192.168.2.21 192.168.2.1 - 192.168.2.254 1

H0m3#

New Member

Re: Router not releasing DHCP addresses, can I clear?

Hmm, just rebooted the router and it fixed it.

Hall of Fame Super Gold

Re: Router not releasing DHCP addresses, can I clear?

Well,you should now be able to observe, as mentioned before, that the router allocated addresses in a linear fashion, spanning the full scope, unless the client request otherwise.

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