Sign in with
Sign up | Sign in
Your question

DHCP Full - How to troubleshoot & fix?

Tags:
  • How To
  • Networking
  • WiFi
  • Servers
  • DHCP
  • File Server
  • Business Computing
Last response: in Business Computing
Share
April 4, 2013 7:50:41 AM

I have had various networking problems over the course of a year. Today, I remoted into my dhcp/file server (running winserv2008r2), and I saw some errors in the server manager under dhcp server. I viewed the details and saw that my dhcp is 91% full with only 21 IPs left. How do I troubleshoot & fix this problem?

More about : dhcp full troubleshoot fix

April 4, 2013 8:08:37 AM

It's not really an error, it's more of a usage issue. You may need more IP addresses on the DHCP scope. You could also lower the lease time freeing up IP's quicker.
If you aren't adding new machines to the network, there may not be any problem at all(you're just using 91% of the IP's), but if you have a lot of machines that come into the network for short periods of time(mobile machines), and then leave, you would want shorter lease times to free up the IP's sooner.
m
0
l
April 4, 2013 8:08:57 AM

How many computers, IP printers, etc are connected to this server? If you're approaching the 255 limit of using a single subnet mask like 192l.168.1.1-255, then you're going to need another subnet and get windows to place nice with 2 of them, which isn't always fun but doable.
m
0
l
Related resources
April 4, 2013 8:15:35 AM

Do you have WiFi enabled on your network? Could it that you have some "freeloaders" on your network? Or - if you allow your employees to BYOD (connect their personal phones / tablets), then probably it's quite normal for you to have that many connections.

If 9% of your DHCP allocation is 21, then you have close to 210 other clients connected, presumably you're working for "large" shop. Look in the DHCP server for client names - they should be familiar to you since you're the guy who installed them ;) 
m
0
l
April 4, 2013 8:18:08 AM

If you are adding and removing connected devices and the DHCP Lease is REALLY long, it'll leave those IP's leased to those devices that are no longer connected. lower the time to something that will arrive soon, so that the non-connected devices and devices that are removed will need to get new IP's when they re-connect.

Or you could redo the IP settings on the DHCP with a /23 network (twice the IP's - 512)
192.168.0.1 would be ur first address (gateway?)
255.255.255.254 would be the subnet mask
192.168.1.254 would be last IP
m
0
l
April 4, 2013 1:02:45 PM

How exactly do I shorten the lease times?
m
0
l
April 5, 2013 3:09:46 PM

No, that is for setting up a new scope. I want to keep my scope but change the lease times...
m
0
l
April 5, 2013 3:12:37 PM

How exactly do I shorten the lease time?
m
0
l
April 5, 2013 4:19:06 PM

puttputtus said:
No, that is for setting up a new scope. I want to keep my scope but change the lease times...


Step 8 shows where the lease time is in the scope, so I would assume you could open your current scope and get to that setting.
m
0
l
April 5, 2013 6:52:32 PM

getochkn said:
Step 8 shows where the lease time is in the scope, so I would assume you could open your current scope and get to that setting.


Yes, but that's in the new scope wizard. Could not find anything for lease time under Options, Properties, etc. under my current scope. I want to avoid deleting the scope I have now and creating a new one with shorter lease time. That would be a pain.

m
0
l
April 5, 2013 7:18:19 PM

puttputtus said:
getochkn said:
Step 8 shows where the lease time is in the scope, so I would assume you could open your current scope and get to that setting.


Yes, but that's in the new scope wizard. Could not find anything for lease time under Options, Properties, etc. under my current scope. I want to avoid deleting the scope I have now and creating a new one with shorter lease time. That would be a pain.



So you don't get the options like here, http://youtu.be/9LzePlKlTng?t=1m57s ignore the Hindu voice, was the first video that came up in google, and I guess you could be googling this yourself too.
m
0
l
!