Three different IP addresses for one MAC address

Started by nedriv

Three different IP addresses for one MAC address   21 March 2015, 07:27

Hello, I just noticed on WiFi Guard that it shows three different IP addresses assigned to one MAC address. However, my DHCP table on my router shows each of the three IP addresses is for a different MAC address. I have attached files showing the output from my router and from WiFi Guard Version 1.0.5

Is there any way to correct the WiFi Guard display of this data?

open | download – WiFi Guard.jpg (92.7 KB)
open | download – DHCP Table.jpg (66.1 KB)
SoftPerfect Support forum - Andrew avatar image

Re: Three different IP addresses for one MAC address   21 March 2015, 16:21

Looks interesting. What happens if you type arp -a at a command prompt after the scan? Does it show the same MAC addresses as WiFi Guard or those from the router?
Thanks for looking at this. Below is the output of the ARP -a command. (Commas & BOLD added for readability)

One of the IP addresses changed to 1.100 from 1.103, but all three IPs show as the same MAC address still.


C:\Users\Ed>arp -a

Interface: --- 0xd
Internet Address , Physical Address , Type , 00-16-b6-15-d8-07 , dynamic , 00-90-96-bf-6f-d3 , dynamic , 00-0f-1f-0b-92-00 , dynamic , 60-02-b4-97-66-ae , dynamic , 00-6b-9e-1d-90-4c , dynamic , 60-02-b4-97-66-ae , dynamic , 60-02-b4-97-66-ae , dynamic , 5c-2e-59-5c-0f-ca , dynamic , b4-74-9f-98-60-2a , dynamic , 00-1e-e5-f7-25-d9 , dynamic , ff-ff-ff-ff-ff-ff , static , 01-00-5e-00-00-fc , static , 01-00-5e-7f-ff-fa , static
SoftPerfect Support forum - Andrew avatar image

Re: Three different IP addresses for one MAC address   22 March 2015, 13:43

Well this apparently shows something is not quite right with the Windows ARP cache. WiFi Guard relies on the Windows networking subsystem and if it returns a wrong result, WiFi Guard displays a wrong result. I would probably recommend to clear the ARP cache by running arp -d * as Administrator.

If that doesn't help, this sort of issue may be caused by a WiFi range extender or similar network hardware in place.
I love this tool

I have the scenario where all the devices connected to a wifi repeater (OpenWRT) are all shown to have the same MAC address as the repeater. Is this just how it is, or have I not quite set up the repeater correctly (I've been having intermittent trouble with it)?
If it helps any, the repeater is set to let the main router hand out the IPs to all devices, including those connected on the repeater side.
SoftPerfect Support forum - Andrew avatar image

Re: Three different IP addresses for one MAC address   21 July 2015, 11:25

I am not quite sure how a WiFi repeater works, but I guess if WiFi Guard (and the OS) sees all those IP addresses on a single MAC address, nothing can be done about that unless there's a setting in the repeater to change this behaviour.
TLDN: Supposed fix for clients showing with the repeater's MAC address is to enable WDS on both the AP and on the repeater.

Apparently this is a known problem with the wireless standard; the address gets lost in translation when getting passed between linking devices like a bridge/repeater and an AP:
Which points to WDS as being the solution.
The first paragraph from wikipedia addresses this exact problem:

Wiki - WDS

The notable advantage of WDS over other solutions is it preserves the MAC addresses of client frames across links between access points.

I'll change the main wireless router to "Access Point (WDS)" and the wireless repeater to "Client (WDS)" Hopefully both chips have the drivers needed to support this mode.

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