Laptops not getting DHCP from server but desktops are.

[edutech4schools]

Well its my first day back and have a head scratcher issue.

 

At some point around lunchtime all the laptops lost network access. Some laptops are wired and some wireless.

 

I have rebooted the server and switches.

 

On my test laptop I can get it up and running if I manually enter the ip, subnet, gateway and dns. for some reason it gives the home ip if set to dhcp.

 

Desktops seem ok and can also get dhcp ok. EDIT, just found some desktops with the same issue

 

We only have 2 main switches (small primary school)

 

any ideas as I am running out of them.

Edited September 5, 2011 by edutech4schools

[ZeroHour]

DHCP full?

Right click on the left pane (can remember where exactly) and look for "Statistics"

[edutech4schools]

No DHCP is not Full. 14% used

[ZeroHour]

Hmmm I have seen a couple of things cause screw ups before, one was Broadcom nics but you have multiple different devices.

The other was DHCP for some bizarre reason trying to give out .0 and .255 ip's and messing up. I just blocked those last bits to cure that but that was 2003 dhcp.

[featured_spectre]

Set the range from .5 to .249 and do IP /release and IP /renew.

[DT2]

switch loop?

 

DT

[FN-GM]

Are they in another vLan? Maybe your ip helper is broken?

[edutech4schools]

more info - Server 2003, no vlans, cant find any loop backs.

 

Just removed server from network and plugged the server into a mini switch and tested with my laptop but still same issue.

[edutech4schools]

Just backedup dhcp settings. re-installed DHCP and restored settings. Still no joy.

[ZeroHour]

Can you try reserving/excluding .0 and .255 ip's from dhcp?

[edutech4schools]

Fixed it but not 100% which fix was the one that worked, but will list all.

 

Removed wds as this can cause dhcp errors as it uses a port number that dhcp uses.

 

Removed VMware server, as this has caused dhpc issues for some.

 

In DHCP / properties / advanced / bindings nothing was ticked and when ticked it would not save. I unauthorized DHCP from ad and restarted the dhcp service, I then was able to tick and re auth with ad.