Solved

How to release unused DHCP ip addresses on cisco router

Posted on 2008-10-21
6
5,067 Views
Last Modified: 2009-12-16
Hi Guys,

I have a block of /25 ip addresses, and I have a dhcp configure on the router, now am receiving messages that says

Free addresses 0
Address in use : 109
Percentage addresses free : 0%

I know that I havent got as many users on that network as indicated, although there are some that comes in once in a while.

Please, how do I release the ip addresses that are not in use.

Thanks
0
Comment
Question by:lawre1108
  • 4
  • 2
6 Comments
 
LVL 7

Expert Comment

by:knightfox
ID: 22765232
Seems that you havent defined your lease time.. so the router is holding addresses I think the default is 8 days.

please run the following.

Router(dhcp-config)#lease DAYS HOURS MINUTES

To define the lease time of the addresses given to the client. You can make it infinite by using this command instead; lease infinite

You can also use the

Router#clear ip dhcp binding *

If you want to clear a certain binding not all of them, replace the * in the previous command with the IP address to be cleared.


/Fox

0
 

Author Comment

by:lawre1108
ID: 22765421
Thanks knightfox,

Apart from clearing the binding on the router does Router#clear ip dhcp binding * have any other effect on the performance of the router and network.

Thanks
0
 
LVL 7

Accepted Solution

by:
knightfox earned 500 total points
ID: 22765897
no.. to make sure you can clear just one entry first...

Router#clear ip dhcp binding x.x.x.x

/Fox
0
IT, Stop Being Called Into Every Meeting

Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

 
LVL 7

Expert Comment

by:knightfox
ID: 22765908
if you run the full clear binding it will force all of you clients to re-negotioate their leases when half of the lease time is reached.  If in the mean time another station is given the address then you  could have some conflicting issues.. Personaly I would clear the ones that you know are not in use, and wait until service ends to clear them all.

/Fox
0
 

Author Comment

by:lawre1108
ID: 22766213
Thanks agin knightfox

That will be big job, where we have over 100 pc and other devices connected to the network.

Is there any way of doing it without any conflict.

Thanks
0
 
LVL 7

Expert Comment

by:knightfox
ID: 22766294
wait until service ends, clear them out once your users go home to be on the safe side...

/Fox
0

Featured Post

Free Trending Threat Insights Every Day

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

In the world of WAN, QoS is a pretty important topic for most, if not all, networks. Some WAN technologies have QoS mechanisms built in, but others, such as some L2 WAN's, don't have QoS control in the provider cloud.
Outsource Your Fax Infrastructure to the Cloud (And come out looking like an IT Hero!) Relative to the many demands on today’s IT teams, spending capital, time and resources to maintain physical fax servers and infrastructure is not a high priority.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

747 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now