IP Conflict

[westy]

Hiya -

 

Ok here is the scenario. It appears a laptop has returned at the start of this term having had a static IP address manually configured (presumably an enthusiastic family member setting it up on a home network), which just so happens to be one of our servers IP address and is therefore causing havoc.

 

I appreciate steps should be in place to prevent such a scenario, namely even the local administrator should be locked from changing IP setting to anything other than DHCP, but in the short term, does anyone have any suggestions of actively finding the culprits hostname perhaps?

 

I have tried temporarily changing the server IP to something else to let the rogue machine take the IP address and then seeing if I can ping/browse/poke/port scan it etc. but pesky local client firewall is blocking any thing like that.

 

Short of mass email saying "If you have a IP address conflict" message please come and see me to everyone I am a bit stumped.

 

Any ideas?

 

Thanks in advance.

 

Andrew

[Michael]

So are you using a Class C type network i.e 192.168.1.1 for example? What IP has the server been allocated? If it is the first, second or third IP personally I would change this immediately to avoid problems.

[leco]

This might help?

[srochford]

eventvwr on the server should give you the MAC address of the machine causing the problem. Do you have a database of MAC addresses? If so, you can then find the machine from that. If not, do you have managed switches which can give you their arp tables - that will let you find the switch port?

[westy]

So are you using a Class C type network i.e 192.168.1.1 for example? What IP has the server been allocated? If it is the first, second or third IP personally I would change this immediately to avoid problems.

 

Thanks for this, as mentioned, I fully intend to put bits and pieces in place (MAC address logging etc) and change the IP schema's in the future but only just started here, so have inherited a rather..hobbyist setup network. Unfortunately, to make this schema change would require downtime and all clients restarted (DHCP environment) so not really a "short term" option.

[Mr.Ben]

Set the lease time that the clients can hold a DHCP address down to a couple of days, then over a weekend all of the clients will need a refresh, even better, use a scheduled batch script to shut them all down on a Friday. Then you have got a few hours to make the changes and test them.