Forum Discussion
Gateway IP address conflicts
Tmobile Gateway router HHCP seems to be assigning unique IP addresses on network devices but getting network warning of IP address conflicts every few minutes?
You can open a console/terminal and ping the network broadcast address 192.168.12.255 and then check the client's ARP table (command arp -a). That should provide some idea of clients that are up and are responding. If you have set any static IP addresses on the network in the 101-254 range then remove the IP for any client with a static IP in that range and use an IP from 2-100. I am pretty sure the DHCP scope runs from 101-254. I never seen an IP assignment below 101 from DHCP. I can assign and I do assign static IPs below 100 so I am pretty sure it is safe to say it is ok and will not duplicate any IP addresses. You can easily test by pinging an IP address you want to set from a client that is connected with a valid IP address. If there is no response then the IP is probably free, assuming it is NOT part of the DHCP scope.
The Arcadyan gateway with its wireless connections and the Ethernet ports are all part of the same Ethernet switch domain and the Netgear 16 port switch with a single connection to that does nothing but extend the switch domain for more interfaces. My suggestion is to temporarily disconnect the connection to the 16 port switch and only have a couple of wireless clients connecting with addressing allocated via DHCP. Look for the problem. If the problem does not exist then add and check as you go with other wireless clients and confirm you do not see the behavior. If you do not see the initial behavior connect the Netgear 16 port switch with a single Ethernet cable and see if the problem surfaces. If the Netgear 16 port switch is a managed switch and has the capability to run a DHCP server get into it and confirm that there is NO DHCP server running. Make sure no clients have bridging enabled.
In effect add one thing at a time. When the problem presents itself carefully examine the configuration of the client that appears to trigger the behavior. DHCP servers can also be running on clients that have 3rd party software running. If there is a loop on the network that will cause frames/packets to spin. Make sure you do not have a loop. The Netgear switch may actually run spanning tree which should prevent any loop on the switch, if it is running. Divide and conquer.
You could leave the setup as is and remove one device at a time and see if the problem stops. If you see the LEDs on the switch all lit up hard or flashing rapidly there could be a loop. If STP is not enabled on the switch and it is a managed switch then enable STP to prevent a loop.
