Automatically Resetting DHCP Leases

I am setting up a DHCP scope on a Cisco 4500X. The DHCP will service new clients and provide a PXE boot set of options. Once built the client will access a Windows based DHCP service.
I understand that the minimum DHCP lease duration is 1 day (24 hrs?). My question is, how can I clear the DHCP leases on a more regular basis say every 4 hours allowing me to use a smaller network IP range for the build network?
Thanks in advance!
Steve

Glad to hear that worked.
It looks like the 4500X IOS-XE does include support for the kron command scheduler utility.
I've not used it personally but from the configuration guide, it looks like you should be able to do something like:
kron policy-list ClearBindings
cli clear ip dhcp binding
kron occurrence ClearDHCP in 04:00 recurring
policy-list ClearBindings
Let me know if it works for you.

Similar Messages

Resetting DHCP without sudo or admin password?

Not sure if this is the right place to post this query but I am trying to reset the DHCP lease automatically so I can create a little "logout" application in my internet café.
I've found the following commands that do the trick but they require the admin password:
sudo ipconfig set en0 BOOTP; sudo ipconfig set en0 DHCP
Any ideas on how this could be done without the admin password? What about with AppleScript?
Many thanks in advance,
Galen

No a hook is initiated by a launch daemon via launchd. So the shell script is being run by the system, not the user (admin or otherwise). ofcourse you would need to be an admin/sudoer to set it.
But why do you want to release the DHCP binding on logout? User processes shouldnt really be doing anything to change that to make it need to be released/renewed unless there is a wider network issue.

How do I revoke a DHCP lease in the 10.8.4 server app?

Hello Everyone,
I have some devices (security cameras) that have successfully requested a DHCP lease. Since then I went ahead and manually created a static reservation for them with a MAC hardware address in the DHCP. For whatever reason they are not switching over to the reserved address. The leases were originally for 1 day. It has been 5 days now. After the first day I switched my lease time to 1 hour. I have done everything short of leaving the devices off for 24 hours.
In Lion server, I could revoke the lease via the gui. No such luck now. My call to Applecare resulted in a "there is no way in 10.8.4 to do this". They said it would switch to the new reserved address after the initial lease period timed out, so I'm hoping the representative was wrong twice. They mentioned a complete lease wipe, but couldn't say if this would cause me to lose my list of reserved static addresses, which isn't an option.
It seems crazy that such a basic feature wouldn't make it into this release of the DHCP service. Any help would be greatly appreciated!

Are there any DHCP queries from the cameras? Check the DHCP server log via Console.app or Server.app (or Terminal.app) for details. (I don't know the 10.8 path to the DHCP logs offhand.)
According to a FAQ over at the Vivotek site, the following is the setup sequence for various recent cameras; the boxes start up in the "I don't have an IP address" self-allocated address block oddly enough, and apparently don't ask for a DHCP address? (You may well be aware of all of this, but this is the block that DHCP clients use when they first communicate with DHCP servers.)
If you are using our new product such as IP7138 / IP7139 / FD7131 / VS7100… etc, no matter your network environment is what, you can always find the camera by Installation Wizard II with the IP address 169.254.x.y.
And then, please double click the camera found by Installation Wizard II or directly type the IP address to your Internet Explorer URL box to access your camera (you do not need to change your PC's IP address). After access your camera, please go to "Network" page to configure proper network settings.
See if the devices are available via mDNS, as well; download the Bonjour Browser and have a look around your LAN. (If you're very lucky, the cameras might be visible and chatting on mDNS.)
Might also try resetting one of the cameras back to factory defaults, and seeing if you can get them to re-ask the DHCP server.
(I've had issues with some HP printers and DHCP clients and IP address assignment, but that's fodder for another discussion. And I also wouldn't rule out a rogue DHCP server, either. I've seen all sorts of unexpected stuff connected to networks over the years...)

Need to renew dhcp lease often

to use the internet (wireless network) i must renew the dhcp lease every time i click a link or open a window. ive reset internet preferences and removed filesharing software. any ideas?

I also have the same problem and it started off small and it took me much trial and error to discover that only by renewing the DHCP lease every time I wanted to open a page could I still surf the net. My internet service provider first suggested that I try rebooting everything and I did -that worked for 5 minutes...then it was back to square one...I spoke with apple they were surprised that it was happening and gave me the option of paying for an over the phone trouble shooting diagnostic explaining that it could be the network card. For some reason last night everything worked perfectly without having to renew the lease.. and then this morning I am once again having to renew with every page. I did try an IP program called IPNETMonitorX but was quickly confused/overwhelmed with tech babble...
Has anyone solved similar issues?

Can not connect with dhcp - renew dhcp lease will switch directly to manuel

If have the following problem
I us apple Airport extreme to connect to internet.
I have 5 Macs, all connecting with airport . They work fine with DHCP. Since 2 weeks I have a problem that one computer – a mac book pro with 10.5.6 will not connect.
When I switch to dhcp and select renew dhcp lease it switch directly back to manuell. I have no chance to connect with dhcp.
Has anyone a suggestion?
Thanks

Wonder why Apple hasn't chimed in on this one...
Whenever you have an issue like this where it's fine, then DHCP stops working for any reason.... Reset the PRAM.
How to:
Apple Logo -> Restart.
After the screen goes black -> Hold down all 4 keys until you hear the third Bong.
"Option"+[Apple Logo OR key to the left of the space bar]"P""R"
After the third BONG or Apple Chime whatever you want to call it. The system's Parameter Ram or to the PC Crowd the CMOS has been reset. This resets your clock, brightness, volume, etc.... So things will get reset along the way but it also resets the IRQ and DMA stats on the logic board. Ala, reseting your Airport's Connection to the logic board, Controllers, etc.

Some Clients wont get DHCP Lease from xServe

Hello,
today we got some strange Network Problems. Some Imacs dont get a IP Adress from our Xserve (10.5). The Xserve tries to offer a adress but the Client wont get them.
The log only says "offer send to xyz-hostname ip-adress"
The strange thing is, when i spoof the Mac Adress on the imac. I get a dhcp lease.
Is there some "Cache" we can reset ? Or simply reboot the Xserve ?
thx

Sure, possibly relevant parts:
errdisable recovery cause udld
errdisable recovery cause bpduguard
errdisable recovery cause security-violation
errdisable recovery cause channel-misconfig (STP)
errdisable recovery cause pagp-flap
errdisable recovery cause dtp-flap
errdisable recovery cause link-flap
errdisable recovery cause gbic-invalid
errdisable recovery cause l2ptguard
errdisable recovery cause psecure-violation
errdisable recovery cause dhcp-rate-limit
errdisable recovery cause vmps
errdisable recovery cause storm-control
errdisable recovery cause arp-inspection
spanning-tree mode rapid-pvst
spanning-tree loopguard default
spanning-tree portfast bpduguard default
spanning-tree extend system-id
vlan internal allocation policy ascending
ip ssh time-out 60
ip ssh authentication-retries 5
ip ssh logging events
ip ssh version 2
interface GigabitEthernet1/0/1
description Gi1/0/1 to CAT-CORE
switchport trunk encapsulation dot1q
switchport mode trunk
interface GigabitEthernet1/0/4
description Gi1/0/4 to RADIUS_serv
switchport access vlan 240
switchport mode access
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
interface GigabitEthernet1/0/8
description Gi1/0/8 to DHCP_serv
switchport access vlan 240
switchport mode access
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
interface GigabitEthernet1/0/11
description Aironet 1141 AIRONET-MO-1
switchport trunk encapsulation dot1q
switchport trunk native vlan 240
switchport trunk allowed vlan 240-246,248,249
switchport mode trunk
interface Vlan240
description Admin_Vlan
ip address 192.168.240.244 255.255.255.0
ip default-gateway 192.168.240.1
ip classless
no ip http server
ip http secure-server

I have to renew DHCP lease every few seconds to stay online

I'm having trouble staying online. I can surf 2-3 pages, then it will not load the next page. I hit renew DHCP lease and the page will load but I am doing this every every 20 seconds. I spoke to my ISP (Time Warner) for almost an hour and could not solve it. They said everything was fine on their end and it sounds like a computer problem. I've used this computer and internet connection for over a year without ever renewing DHCP lease now I do it all the time. Any advice would help.

I'm having the exact same problem. Sometime the pages will work for a while. Then the internet will start dropping out for a few days at time.
I've reset and restarted everything, tried everything that I can think of. The only thing that seems to help is to renew the DHCP lease whenever it starts to happen. It will load one, maybe two, websites, and then the browser just says "connecting to (insert website here)"
Please help, Next step is calling up AppleCare, which I would rather not do if I could. I'm a college student and i use my laptop to take notes during classes. (I type much faster than I can write)

How do I fix that I constantly having to renew dhcp lease?

I am constantly having to renew my dhcp lease. Can anyone help resolve this issue?

I was having this problem the other night after I finished doing a massive upgrade to our Home Network (New Router, Modem, Cabling, Etc)
I had to reset my DHCP lease every few minutes, in the end I found it was the IP Address kept setting itself to other items on the Network, I have some items coming through on wired (ethernet) and some were checking in on WiFi (Airport Extreme) the Mac Mini would grab an IP address that it thought was available and then we would have a clash.
I was watching the items on my Routers Attached devices screen, The Mac Mini would show up on the page with its new address (after hitting the DHCP Renewal button) then something elese would check in with that exisiting IP Address, clash and the Mac Mini would need the DHCP lease renewed again.
I'll be the first to admit my Networking knowledge is limited (and I'm learning more all the Time) but I simply went into the preferences panel and set the IP address manually.
1. I went into preferences and selected Network
2. Set Configure IPV4 to: using DHCP with manual address
Now it helped I had my NetGear Routers "Attached devices" Page open here so I could see the address of everything else on my network (I went and switched everything on that was web connected so it would be logged in and running on the network) I looked at the last digit or 2 of every item on my network and then set my new IP address.
3. To ensure I wouldn't have any more clashes I set my new IP address far away from the the others* your only changing the last digit or 2 of the IP address, so in the case of my Mac Mini it went from xxx.xxx.02 to xxx.xxx.0.52 (note the x's are normally your IP address numbers)
*I originally set it to xxx.xxx.09 but I since found the TV had that IP address (The one thing I forgot to check the previous night) so I this is when I decided to set it far away from the rest of the bunch by setting it to .52 (Note: 52 was just the 1st number to pop into my head)
Now that was over a week ago and since then I have had no more issues on my Network, so far everything is running smooth and fast.
This is probably not the ideal way to fix this issue, but so far it is working, hopefully someone with quality networking experience can chime in with a more permanent solution.

What are DHCP settings and what is a DHCP lease

My macbook has decided to stop logging on to my wifi router automatically.
Seems the DHCP settings are wrong with an inappropriate IP address and Submask coded applied.
When I change them back manually to what they were the computer says it is logged on to internet but refuses to open any internet application?
I have tried the DHCP lease renewal prompt but still will not award appropriate IP or Submask code

Hi RobertaMcC,
Are you having trouble with a Wi-Fi connection or a wired (Ethernet) connection to the internet? DHCP is a communications protocol that assigns each computer a unique IP address on the internet. I'll include the information you specifically requested first, and general troubleshooting steps as well.
OS X Yosemite: Renew an IP address from the DHCP server
https://support.apple.com/kb/PH18513?locale=en_US
Here is an overview of the troubleshooting steps for a Wi-Fi connection:
Wi-Fi: How to troubleshoot Wi-Fi connectivity - Apple Support
https://support.apple.com/en-ca/HT202222
Hope that helps ...
- Judy

Does anyone else have to renew their DHCP Lease every 30 seconds when using the internet?

Everytime I want to use the internet for surfing the web or browsing iTunes etc I have to go into System Preferences and navigate through to a button that says "Renew DHCP Lease". If watching catch-up TV online I have to click this button every 30 seconds or so because the programme freezes, and if I'm surfing the web or browsing iTunes I have to click it every time I want to update the content of the page. Does anybody know what my problem might be?

This Fix has got things working for me.
I have reprinted this response from another thread I have made (Repost) A number of people were asking me about my fix, so I have expanded my response to hopefully offer a little more clarity.
I was having this problem the other night after I finished doing a massive upgrade to our Home Network (New Router, Modem, Cabling, Etc)
I had to reset my DHCP lease every few minutes, in the end I found Mac Mini's IP Address kept setting itself to other items on the Network, I have some items connected on wired (ethernet) and some were connected on WiFi (Airport Extreme) after clicking the DHCP Lease Renew the Mac Mini would grab an IP address that it thought was available but then another item on my network would "check in" then we would have a clash, The Mac Mini was grabbing what it thought was an available IP address, the DHCP Renew button was not setting the Mac Mini's IP number far enough away to stop the clash.
I was watching the items on my Routers Attached devices screen, The Mac Mini would show up on the page with its new address (after hitting the DHCP Renewal button) then something else would check in with that exisiting IP Address, clash and the Mac Mini would need it's DHCP lease renewed again.
My Network consists of:
- Mac Mini (Wired)
- Acer Laptop (Wired)
- PS3 (1) (wired)
- Apple TV (wired)
- Airport Extreme (wired and looking ater WiFi duties throughout the house)
- PS3 (2) (WiFi)
- TV (WiFi)
- iPad (WiFi)
- Nexus 7 (WiFi)
- Printer (WiFi)
I'll be the first to admit my Networking knowledge is limited (and I'm learning more all the Time) but I simply went into the preferences panel and set the IP address manually.
1. I went into Preferences and selected Network
2. Set Configure IPV4 to: using DHCP with manual address
Now it helped I had my NetGear Routers "Attached devices" Page open here so I could see the address of everything else on my network (I went and switched everything on that was web connected so it would be logged in and running on the network) I looked at the last digit or 2 of every item on my network and then set my new IP address.
3. To ensure I wouldn't have any more clashes I set my new IP address far away from the the others* your only changing the last digit or 2 of the IP address, so in the case of my Mac Mini it went from
xxx.xxx.02 to xxx.xxx.0.52 (note the x's are normally your IP address numbers)
*I originally set it to xxx.xxx.09 but I since found the TV had that IP address (The one thing I forgot to check the previous night) so I this is when I decided to set it far away from the rest of the bunch by setting it to .52 (No specific reason for 52, that was just the 1st number to pop into my head)
Now that was over a week ago and since then I have had no more issues on my Network, so far everything is running smooth and fast. (It has now been over 3 weeks since I posted this, and everything is still working perfectly, I suggested this solution to 2 friends having the same issue and it also fixed there problems as well)
I'm not saying this is the be all and end all to the problem, there must be a more permanent solution out there, but this is working for me so far.

MDT 2013 - A Connection to the deployment share could not be made - DHCP Lease was not obtained

First, let me give you some context:
Framework: MDT 2013 with MS SDK 7.1
Task Sequence: Standard Client TS with sysprep and capture.
Target workstation (build workstation): VM Guest on ESX 5.5 host, 8 vCPU, 8GB RAM, LSI Logic SAS Controller, E1000 NIC, SSD DAS
Behavior: The VM loads and installs the OS fine in PE, VM boots into OS successfully and resumes the TS, after the first system reboot, the error message occurs and it reads:
A connection to the deployment share (\\*********\DeploymentShare$) could not be made. DHCP Lease was not obtained for any Networking device! Possible Cause: Check physical connection. Retry:...... Cancel:.....
While observing this error, I didn't notice the NIC hadn't completely initialized and obtained an IP yet (network adapter icon in systray), additionally hitting retry after the NIC was initialized resumed the TS.
This behavior reoccurs with several subsequent reboots until a few more applications (Citrix Receiver, VMware Tools) with services are installed which seem to then slow the system boot-up time and then allows the TS to start after the NIC has initialized.
From several posts I've read on this forum, this particular behavior was alleviated by a "wait for IP lease" mechanism built into the TS engine which was introduced in MDT 2010 SP1, I wasn't able to find any other confirmation whether
this mechanism is still in effect with MDT 2013. Another point worth mentioning from several other posts I was able to find is that this behavior appears to manifested itself on target workstations with SSDs, which would somewhat explain the faster
TS load time vs waiting for an IP lease. I've also tried to replicate this behavior in a non-SSD and low-performance VM environment and I wasn't able to replicate it.
My question: Does anyone else have experienced this behavior with MDT 2013 and if so, how did you resolve it? Or is this a bug?

I have this issue intermittently as well. For us, it coincided with the deployment of IP phones, which meant PoE switches all around. However, the problem persisted even after we turned off PoE to the ethernet ports from which we normally PXE
boot.
As this issue has been intermittent, I've backburnered it. When it does happen, I just wait for the lease to arrive then rerun the wizard.
Thanks for the feedback, that's true the TS can be resumed manually once the lease has occured but it defeats the purpose of an automated TS if I have to keep an eye on it and intervene if I need to.
The network guys here recommended putting wireshark or network monitor on it and figuring out just what the heck is going on. Basically, what Keith Garner said. They also disabled PortFast awhile back to see if that made any difference, and it did
not.

TS1388 After one or two websites the search "freezes". To rectify this I need to go into "Network" and press "Renew DHCP Lease" on my imac 10.6.8

After one or two websites the search "freezes". To rectify this I need to go into "Network" and press "Renew DHCP Lease" on my imac 10.6.8TS1317 - Mac OS X: Troubleshooting a cable modem, DSL, or LAN Internet connectionAny help?

Check your computers time and date are correct, and updating to your location via Apple's servers.
WiFi, Internet problems, possible solutions

[SOLVED] Hostname not showing in DHCP lease list

This is a brand new installation using the new systemd base.
Installed openbox as window manager and Network Manager.
What did I miss that the hostname of this computer (opus) is not showing up in the DHCP Leases list?
When I connect to the network using Network Manger(DHCP), hostname is not sent to the DHCP server (DNSmasq). It shows up as a "*":
DHCP leases
Hostname    IP-address    MAC-address    Lease expires
*    192.168.10.100    XX:XX:XX:XX:XX:XX Nov 28th, 19:34
*    192.168.10.59    XX:XX:XX:XX:XX:XX Nov 28th, 19:23
alarmpi    192.168.10.69    XX:XX:XX:XX:XX:XX Nov 28th, 16:56
RM696    192.168.10.97    XX:XX:XX:XX:XX:XX Nov 28th, 18:23
(I blanked out the MAC-addresses.)
The first entry is connecting through wireless. The second is wired.
At the command line:
hostname
opus
hostname -f
localhost.localdomain
/etc/hosts:
# /etc/hosts: static lookup table for host names
#<ip-address> <hostname.domain.org> <hostname>
127.0.0.1 localhost.localdomain localhost opus
::1 localhost.localdomain localhost opus
# End of file
What file do I need to change and how?
Updated:
1) I created a /etc/dhclient.conf file and added:
send host-name "opus";
request subnet-mask, broadcast-address, time-offset, routers,
domain-search, domain-name, domain-name-servers, host-name;
and rebooted.
This had no effect.
2) Just for kicks, I uninstalled Network Manager and installed Wicd.
This DID send the hostname and it displayed on the DHCP Leases List. But it also had the effect of turning off the WiFi radio.
I did try to turn it back on: Went to the BIOS, made sure it was on (it was). Read some posts about power savings and what to do (tried them, didn't work).
So I uninstalled Wicd, re-installed Network Manager and I am back to where I was.
Last edited by dastagg (2012-11-29 11:15:11)

Sorry, forgot to add this:
https://bbs.archlinux.org/viewtopic.php?id=152376
Follow the instructions on the bottom.

Ipod Settings Automatically Resetting

My iPod settings automatically reset to default after it turns on from sleep mode or being docked to the computer...I have also tried restarting the iPod...but nothing seems to work...any suggestions to fix this?

MisHann,
http://docs.info.apple.com/article.html?artnum=61685
http://docs.info.apple.com/article.html?artnum=107970

RV180W firmware 1.0.5.4 DHCP lease problem

Yesterday I upgraded my RV180W to firmware 1.0.5.4. Today the only machine that we have with XP can't get a DHCP lease (we have some 20 machines that can that all have W7 o W8.1). Also none of the iPhones nor Androids that connect via wifi get leases either and thus have fallen back to 3G.

Hello,
First of all I want to say that I'm sorry you are experiencing an issue with the device after the firmware upgrade.
Now, we have tested this device with the new firmware on our lab and we are not experiencing the same issue, which leads me to believe this may be an issue with your particular configuration or network topology.
We would love to have the opportunity to troubleshoot this issue on the Small Business Support Center. If you are still under support with the device, give us a call and we will be happy to assist you.
If you are not able to or are out of support, then please provide as much information as possible in regards to your current configuration as well as network topology, maybe a detailed network diagram could be helpful to so that we can have a better idea of that the issue could be.
I hope this was helpful.

Automatically Resetting DHCP Leases

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