Stupid IP Address conflict ...

[thecomputerguy]

I have a client with a Plotter printer with a hard-coded IP. I for whatever reason during install didn't reserve the IP (my bad). It's worked fine up until this point (2 years) but for some reason some other device came in and swooped up the IP the plotter is supposed have. The device is live on the network but I called over there no one seems to know what this new device is. I don't think it's a phone or tablet because the DHCP entry in the 2012R2 DHCP snap-in isn't listed like an iphone normally would (bob-iphone.contoso.local).

The printer people came out and diagnosed this by unplugging the plotter and pinging the IP showing it as active. I'm not sure why they just didn't change it on the spot but they didn't.

Does anyone have any creative way of getting this IP back so I don't have to have the printer people back out to hard-code a new IP then reconfigure 20 workstations for the new IP?

I know I can delete the DHCP entry but the device will still have it until it's turned off or rebooted.

Can I reserve a new IP for it based on the MAC and set it to expire or something?

 

[ComputerRepairTech]

Did you try searching the manufacturer via MAC ID? might give you a big clue as to what the new device is.

I recently could not figure out for the life of me what this unknown device was on my network, it ended up being a ring chime which is an extra speaker for my ring doorbell xD. I'm not sure I would have ever figured it out without searching via MAC id.

 

[thecomputerguy]

Did you try searching the manufacturer via MAC ID? might give you a big clue as to what the new device is.

I recently could not figure out for the life of me what this unknown device was on my network, it ended up being a ring chime which is an extra speaker for my ring doorbell xD. I'm not sure I would have ever figured it out without searching via MAC id.

Good idea ... MAC lookup comes back with

BILLIONTON SYSTEMS, INC.

So .. I'm pretty sure they are just a wireless card manufacturer ...

 

[RCHavok797]

You should be able to tie the mac address to a port on a switch unless you just have unmanaged switches.

 

[RCHavok797]

I just reread your post and the simple solution is to either exclude the IP of the printer in DHCP or create a reservation for it. If the device that is conflicting is grabbing an address from DHCP then problem solved.

 

[nlinecomputers]

You don't have your DHCP server setup correctly. The IP range you place your printer should NOT be in the scope assigned to DHCP.

 

[nlinecomputers]

 

[thecomputerguy]

You don't have your DHCP server setup correctly. The IP range you place your printer should NOT be in the scope assigned to DHCP.

Yes you're right, they had a funky IP scheme when I started some work over there and I left it as is because of all the weird random stuff they had. I should have re-done the whole scheme.

 

[thecomputerguy]

The device being wireless means I can disable the AP's and remove the DHCP entry and then reserve the Plotter then re-enable the AP's ... lets see if that works.

 

[freedomit]

Also if it's a Windows DHCP server it's always a good idea to enable conflict detection as an extra precaution

 

[nlinecomputers]

That will not work but it should cause that device to have a conflict error. You'll find it that way. If the device is a PC you ought to be able to find it in AD.

 

[thecomputerguy]

I disabled the AP's and was still able to ping the device ... and it doesn't show up in AD so it isn't a PC.

 

[nlinecomputers]

I disabled the AP's and was still able to ping the device ... and it doesn't show up in AD so it isn't a PC.

Put the IP in your web browser. Maybe it has a web GUI and you figure out what it is

 

[Altster]

BILLIONTON SYSTEMS, INC.

http://www.billionton.org/en/
Bluetooth adapter most likely. Something new that someone has walked into the office with.

 

[thecomputerguy]

Put the IP in your web browser. Maybe it has a web GUI and you figure out what it is

There was no GUI for the specified IP

 

[thecomputerguy]

We figured it out!

One person at the office remembered that they had someone come in and replace their old postage machine with a new one that is network accessible. We unplugged that and I couldn't ping, plugged the plotter back in, pinged fine ... Reserved the IP and plugged the postage meter back in ...

Woohoo!!

 

[nlinecomputers]

We figured it out!

One person at the office remembered that they had someone come in and replace their old postage machine with a new one that is network accessible. We unplugged that and I couldn't ping, plugged the plotter back in, pinged fine ... Reserved the IP and plugged the postage meter back in ...

Woohoo!!

I'd find that device and reserve it too.

 

[NETWizz]

What kind of network switch(s) do they have?

You can usually unplug the known device like a plotter and then trace it out pretty easily on any managed switch.

Something like:

Switch#ping 10.1.2.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.2.3 timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/6/8 ms

Switch#:show arp | include 10.1.2.3

-------------------------------------------------------------------------------
0/3/CPU0
-------------------------------------------------------------------------------

10.1.2.3 - 000c.cfe6.3336 Dynamic


Switch#show mac address-table address 000c.cfe6.3336
Mac Address Table
-------------------------------------------

1 000c.cfe6.3336 DYNAMIC Gi0/16



Then follow Gi0/16 to the patch panel and/or offending device.