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Duplicate Mac Addresses causes IP conflict message

Posted: Thu Oct 27, 2016 9:22 am
by ksharf
Hi all,

I have an issue that I've been unable to resolve.

I have a DSC1832 with an EVL4 board. As the Alarm panel is on the other side of the house from the Netgear router, i have a
Netgear WIFI Extender (N300-WiFi Range Extender.Model: WN3000RP) with an Ethernet Port. The EVL4 is connected directly into the WIFI Extender. On the router, i have configured static IP's via DHCP for both the Netgear Wifi extender and the EVL4. The Netgear Wifi Extender is interesting because it assigns virtual mac addresses to all devices attached to it. The Netgear router when viewing attached devices, shows a slightly different MAC Address to that displayed on the eyez-on web-site. This is , however, not an issue and the entire setup works flawlessly.

However, at least once every two weeks, the eyez-on site complains that there is an IP conflict. There is no disruption in connectivity between the EVL4 and the app. When viewing the attached devices report on the Netgear router, the IP's are all unique as per the dhcp configuration. However, the router reports the same MAC address is assigned to both the WIFI Extender and EVL4 device. The MAC address is that of the Wifi Extender. Again, connectivity is not an issue, there are no dropped packets and the site works just fine. I can access the EVL4 device page and Wifi Extender configuration page as per the dhcp static IP's. The annoying part is the error message that appears complaining about a duplicate IP. The functionality of the system is not impacted.

The issue in this case is not a duplicate IP but a duplicate MAC Address. In order to resolve the issue, i reboot the Wifi Extender. When viewing attached devices, the MAC addresses are no longer repeater for the IPs of both the Wifi extender and EVL4. However, the error message remains on the portal until a reboot command is issued thru the eyez-on portal.


Its all a little confusing. The error message appears complaining about a duplicate IP when the issue is a duplicate MAC address. A duplicate MAC address should never occur and for the most part does not cause any issues. Why this occurs, i have no idea.

Re: Duplicate Mac Addresses causes IP conflict message

Posted: Thu Oct 27, 2016 10:02 am
by GrandWizard
The Duplicate IP Address error is somewhat generic but in 90% of the cases it is indeed the problem. The real problem is that you have 100% return packet loss which means the servers are getting the status packets from the Envisalink just fine, but none of the return traffic is making it back. That is because of your duplicate MAC problem (The router is getting the packets, not the Envisalink). When you have this siutuation you will not receive any alerts nor will you be able to control your alarm panel.

In any case, you need to fix the problem with the Netgear extender. What you describe is pretty strange and I don't understand the point of "virtual MACs" as by design, all MACs around the world are unique.

Re: Duplicate Mac Addresses causes IP conflict message

Posted: Thu Oct 27, 2016 10:42 am
by ksharf
Thankyou for the quick reply.

However, i do not think think there is is any packet loss as i do get the alerts and can fully control the panel via the eyez-on portal. The error message is annoying , however, control of the panel via eyez-on is still fully intact.

Re: Duplicate Mac Addresses causes IP conflict message

Posted: Thu Oct 27, 2016 11:07 am
by GrandWizard
Submit a tech support request and we can help you further. That message only appears at 100% packet loss.

Re: Duplicate Mac Addresses causes IP conflict message

Posted: Thu Oct 27, 2016 11:37 am
by ksharf
will do..thankyou

Re: Duplicate Mac Addresses causes IP conflict message

Posted: Sun Oct 30, 2016 8:14 am
by Jeff H
What is the router model? I am not familiar with setting static client IP's at the router. I would leave the router as the DHCP server, set a static IP for the extender on the extender in the extender's GUI, and turn off if possible the extender's DHCP server ability, let it pass DHCP duties to assign client IP's to the router. And leave the EVL-4 on dynamic.