DHCP renewal issues - limited connectivity

[MK-2]

I have just imaged and set up 4 new machines for the staffroom. I ran newsid after so I know each has a completely separate SID.

Two of them logged on OK, the other two say domain is unavailable.

I go in locally and the network card is saying limited or no connectivity. I can pull the cable out, plug it in and sometimes this will get an IP, other times it will just sit there saying acquiring.

It seems to be happening randomly on some machines. I have checked DHCP and we are nowhere near capacity of leases (11% used).

 

I'm still trying to find all comms cabs in the school so I can't say whether its a dodgy switch, or loopback somewhere else.

The one thing I have noticed is that the cab in my office is flashing like there is a lot of data going through it, sort of how it did at my old place when I was ghosting. But there are no ghost sessions running and I'm not doing anything, and pings are still normal reply times.

I don't want to try too much because I've only been here a month so don't want to royally screw things up, but any advice on what I could look at would be very much appreciated!!!

[Face-Man]

I had a similar problem from some of the following

 

1) a loop on the network

2) spanning tree enabled on some switches but not all

3) A wireless hub plugged in in the science dept going potty

 

It may also be a DNS attack or a doggy network card / switch.

 

Do you have managed switches ? can you get the web interface up and see the traffic loads on particular ports.

 

In the end I've resorted to unplugging everything one at a time until it got better and seeing where that was

[pooley]

Had issues today after rebooting server (Windows updates) over the weekend, ip renewals were very hit and miss (more miss)

 

Checked the Cabs and switches all seemed fine, in the end I moved my DHCP database to another server (and back) and its working ak again.

 

No idea why, or even if yours is a similar issue

 

Si

 

Server 2003 btw