Author Topic: Duplicate IP address possibly.  (Read 9006 times)

Offline pakman

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Duplicate IP address possibly.
« on: September 27, 2013, 09:55:40 AM »
On of our sites reported that when they call out local or LD they get dial tone then dead air after they make the call if they hang up and try again it works usually the 2 or 3rd time.

I looked at the logs and have two identical logs with only the MAC being different.
"Possibly 2 computers with the same IP address (x.x.x.x).One of those computers has MAC address 08:00:0f:XX:XX:XX. If this IP is used by the Mitel RTC card, E2T card, a phone or router, there may be disruption in telephone service."

Now the IP address the log is displaying is the IP of our switch and so Is one of the MAC's the other MAC is not a phone as our DHCP doesn't give out addresses in this space and there is only a RTC card. This mac is very close to the one in the log except it's off by one digit.  This is a very small site with only 5 PCs and phones is there anyway else to track down the 08:00:0f:XX:XX:XX on the controller?

There is no way the controller or the other dhcp server is handing out the duplicate IP as that range doesn't exist in either of them. They do have printers on site but those are in a different subnet than this duplicate IP.

Thanks,



Offline jrg0852

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Re: Duplicate IP address possibly.
« Reply #1 on: September 27, 2013, 10:43:57 AM »
Go to IP Telephone Inventory and search the MAC(s) in question.

Offline pakman

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Re: Duplicate IP address possibly.
« Reply #2 on: September 27, 2013, 01:02:22 PM »
yes, I have already done this. I guess I was wondering if there was a command one could type in on the pbx searching for a particualr MAC? I cannot find the one mac anywhere.

Offline johnp

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Re: Duplicate IP address possibly.
« Reply #3 on: September 27, 2013, 01:08:04 PM »
What controller model?

Offline lundah

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Re: Duplicate IP address possibly.
« Reply #4 on: September 27, 2013, 01:37:19 PM »
yes, I have already done this. I guess I was wondering if there was a command one could type in on the pbx searching for a particualr MAC? I cannot find the one mac anywhere.

"arptabShow" from the RTC console prompt will tell you the MAC address of every device that's communicated with the 3300 within the last 10 minutes or so.

Offline pakman

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Re: Duplicate IP address possibly.
« Reply #5 on: September 27, 2013, 03:32:20 PM »
Hello,

The box is a CXi. I am not sure what the RTC console is but when I go into maintenance commands and do a arpshow I don't have duplicate IP addresses. The intresting thing is when I log into the switch and lookup the mac address of the Mitel device that say's the IP may be a duplicate when in fact it's my switches IP. I look up this mac and it say's whatever this is it's plugged into port 3. I had the office folks tell me what's in port 3 and it's the Milte box itself. The MAC of the Mitel box itself is very close to the duplicate mac address maybe there really are the same as this would make sense.

Offline pakman

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Re: Duplicate IP address possibly.
« Reply #6 on: September 27, 2013, 03:43:10 PM »
This might make more sense. when I do a show mac address on the HP switch port 3 which is the port the Mitel controller is plugged into has offered up two mac addresses one of those mac adddresses is the culprit in the log with the duplicate IP.  I am not sure why the Mitel box itself would offer up two mac addresses to the same port any ideas?

Offline x-man

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Re: Duplicate IP address possibly.
« Reply #7 on: September 27, 2013, 03:44:46 PM »
We get this quite a lot and have never bottomed it yet, same as you when we do the search and look at the port its the CX itself....never caused an issue with the network yet (except the once when there was a duplicate address but that was the IT guys problem giving a piece of equipment an IP in the scope.....

Offline lundah

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Re: Duplicate IP address possibly.
« Reply #8 on: September 27, 2013, 04:05:18 PM »
The RTC console is accessed via the DB-9 RS-232 serial connector (19200bps, 8-N-1) on the front of the controller marked "Maintenance". Be careful when using this interface, you can easily do pretty destructive things like rebooting the system or deleting critical files from the filesystem very easily from this interface.

As far as how the controller can have multiple IP addresses, it has an internal L2 switch that is configured via the System IP Configuration form, so check that for your duplicate IP. That also explains why the mystery MAC is only one off from the known RTC MAC address, as they're both in the controller itself.

Offline pakman

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Re: Duplicate IP address possibly.
« Reply #9 on: September 30, 2013, 09:55:43 AM »
Thanks Lundah!

I checked that form and somehow the l2 IP is the same as my switches' IP not sure how I didn't catch that earlier. There are no phones plugged directly into the pbx so I am going to re IP it and hopefully cause no issues in the process.


Offline lundah

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Re: Duplicate IP address possibly.
« Reply #10 on: September 30, 2013, 04:37:06 PM »
You'll have to reboot the controller for the change to take effect.


 

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