Stop Alien router from pulling two DHCP leases in bridged mode?


  • My Alien router pulls two DHCP leases from my upstream router when I have the Alien in bridged mode.

    In the iOS application on my phone I go to the Diagnose tab and I see:
    IP Address - first address which uses the MAC address of the LAN Network

    In my upstream router I can see a secondary DHCP lease pulled from the Alien router. It's very clearly the Alien router based on the hostname of the device. The MAC address used does not show up anywhere on the iOS application in the about page.

    Can we stop this behavior so the device only pulls one address from DHCP? I shouldn't have to have two static leases for this device the second of which doesn't show up anywhere in the iOS application.


  • Hi @arfett - is your Alien pulling the 2 IP addresses simultaneously in Bridge mode?

    That would be unusual

    AmpliFi routers historically have a WAN MAC and a LAN MAC and present a different MAC address upstream depending on whether it is in DHCP mode (WAN MAC) or Bridge mode (LAN MAC)

    So an upstream primary router will often have a record for both, but only one active at a time

    In the latest HD Router firmware the notes say only one MAC address will be used from now on

    The dual MACs were initially needed to implement HW NAT, but that is being changed somehow now

    So we believe Alien will get the same update as well and there will be only one MAC presented to the upstream router in the future


  • 0_1584177552937_alien-dual-dhcp.png

    Yes it pulls two DHCP leases simultaneously. In the image you are seeing hostnames I have applied to it manually but the secondary IP shows up as like ALN-FN-XXXX or something like that when it requests the lease so it's obviously the Alien router. I also only have two devices on WiFi at the time I see this and both of those are accounted for.

    The strange thing is when I look up that C6:22... MAC address online it can't find a manufacturer for it and it does not show up in the list of MAC addresses on the device I see on the iOS app. I have no idea what this phantom MAC is used for on the Alien or why it would need a DHCP lease.


  • Hi @arfett - you might want to generate a Support Info file and email it to @UI-Brett & @UI-Karlis to see what is going on


  • Hi @arfett - do you have Guest access enabled or inactive?

    The ‘x6’ MAC addresses in my Aliens are associated with the Guest WiFi

    ‘x0’ MAC’s are the main Router and ‘x2’ MAC’s are BlueTooth

    The second IP address may be for Guest segregation


  • @Derek-Saville Guest WiFi disabled and never used. Just use it for my phone, laptop and Amazon FireStick at the moment now that I've wired in other devices to my other networking gear.

    I have all 3 radios enabled with separate SSIDs. Single SSID for each radio.


  • Hi @arfett - I just checked the primary routers in front of 2 bridge mode Alien sites, and both only have the fixed reserved IP address for the Aliens’ LAN MAC assigned

    The only other IP addresses associated to the the Alien name are ones being dynamically handed out to Teleport clients, both using the Teleport App and the remote Router-to-Router Teleport feature

    The Teleported clients appear as additional Ethernet devices with the same AFI-ALN... names appended with “-2”, “-20”, etc. as the Alien router, but I can see they are using the IP addresses of the overseas clients

    My bridge mode Aliens are definitely only getting and using one IP address themselves

    So if yours is pulling two, then I would suggest sending Support Info files to @UI-Karlis and @UI-Brett to see what is going on


  • @Derek-Saville This is definitely what's pulling the address. I looked at the teleport device (my iPhone) and it has the IP address from the 2nd reservation. I haven't used the teleport feature in several weeks so it's strange to me that the Alien would have that MAC active and pulling a lease at boot time but at least now it is explained. I'm actually okay with this being the case for my usage.


  • Hi @arfett - the router will keep an IP reservation open indefinitely for Teleported client devices, even if inactive, until you explicitly “Close Teleport Connection” for the client


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