Networking & Wireless forum

Question

Same MAC addressing showing with two different IP addresses

by AllOtherUsernamesTaken / November 8, 2012 11:03 PM PST

The same device MAC number is listed twice. It is shows to have different IP addresses.

____IP________________________MAC
10.201.85.19______________00:14:7D:68 . . . .
192.168.1.14______________00:14:7D:68 . . . .

The device is my wife's Samsung phone. Should I be worried that my network is being compromised?

Answer This Ask For Clarification
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Clarification Request
Update for today

I went and looked at attached devices today and it was still showing two different IP addresses for the same device MAC but the IP address was different.

____IP________________________MAC
10.71.101.150______________00:14:7D:68 . . . .
192.168.1.14______________00:14:7D:68 . . . .

Any idea why this happens or if it is cause for concern.

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Actually it's no mystery.
by R. Proffitt Forum moderator / November 9, 2012 1:00 AM PST
In reply to: Update for today
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Security
by AllOtherUsernamesTaken / November 9, 2012 1:24 AM PST

I am using WPA2-PSK [AES]. I was not using MAC address filtering to limit access. I was just looking to see what devices were attached to the network as I have recently added a new blu-ray player. That is when I noticed the issue with my wife's samsung phone's MAC address appearing twice and assigned 2 different IP addresses. Was just wondering if this was cause for concern. On a side note my nearest neighbors are over a mile away.

I am using a netgear wndr3800 router

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Samsung has been caught red handed
by R. Proffitt Forum moderator / November 9, 2012 1:28 AM PST
In reply to: Security

Using the same MAC address across devices. If you think about it and how it costs a little in manufacturing you see why they drop the ball.

SECURITY? MAC addresses do not add security. There are some that haven't caught up with the times and will tell you that you can filter such but since we can change the MAC at will on many devices, the MAC addresses is now not a security item.
Bob

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Any idea
by AllOtherUsernamesTaken / November 9, 2012 7:31 AM PST

Any idea why one is using 192.x.x.x and the other 10.x.x.x IP address?

I am using the router as a DHCP Server and have it configured to start at 192.168.1.2 and end at 192.168.1.254

I have no idea where the 10.x.x.x is coming from and why it is showing under attached devices at that address IP.

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Can't guess with the limited information.
by R. Proffitt Forum moderator / November 9, 2012 2:16 PM PST
In reply to: Any idea

All I can comment on so far is the MAC address issue is well known in the circles I run.

I would be guessing badly given the story so far.
Bob

All Answers

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Answer
Two IP adresses for one MAC
by cabhan / June 8, 2013 3:08 AM PDT

Hi there.

I can see that this thread is a little old but the answer to this issue is to do with the phone having an IP address for your router and one for your phone networks providers GPRS service. The later IP address will change quite a lot. If you do a WhoIs lookup for the odd IP address you will probably find it comes out to your phone network provider. For example I often get 31.83.xx.xx which is Orange. I also get quite a few 10.xx.xx.xx ones as well.

If you don't believe me, the simple test is to turn off your phones packet data connection (usually found in the mobile network settings). Refresh your router ARP table and you will find the spurious IP has now gone.

Nothing to worry about. Very common on Android devices.

Regards, Nick.

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