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Solved:RT-AC68P Assigning Static IP's within DHCP Range

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Kevin G.

New Around Here
Hello, new here...registered for a solution to my plaguing IP issues. I have searched (including here) for something related to my problem, but all I see are "how to" articles.

I have my DHCP range set to start at 120, as I use the lower range to assign static IP's for devices that I require to have a reservation (2 servers, AP's, a Media device, and until recently Xbox) all of which I set at the client side.

For a while now, I have been having trouble with running out of DHCP addresses (usually when my daughters come home, with respective boyfriends). I also try to limit how many devices are on the network without my knowledge, for security reasons. There was a time when our house was the central point for friends to show up, and my network password was handed out freely...
I have not been able to discern why, and in lieu of opening more DHCP IP's, decided to finally get this resolved.

When I look at connected devices, I see several assigned as static, not created by me. They are also within the DHCP range. How does this happen? I attempted to release all clients, but cannot find how to do this effectively. I have turned off DHCP, restarted the router, and enabled DHCP. the static IP's remain. I have turned off WAN, and re-enabled. Statics remain.

I have not taken the time to define what all these devices are, but I now know why I run out of open addresses when the kids are all here. These static IP's are eating up reserved spaces.

Is there any way to clear these addresses, and get my defined DHCP back?
Any assistance is appreciated, thanks for your time.

(The addresses below 120 are assigned by me)



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Change the password(s).
 
The client list can be misleading or downright wrong. Particularly items marked as static, which tends to indicate a device on the network that isn't known in DHCP and isn't wirelessly connected to the router (therefore it assumes it's static). Note that "static" is not the same as "manual".

A classic example of this is a device connected indirectly to the router via a switch or access point. If the router is rebooted it looses it's list of DHCP assigned devices. However, clients that are indirectly connected do not detect that the router has restarted (their network interface remains up) so there is no reason for them to reacquire a DHCP lease. After the reboot the router can see they are on the network (because of their ARP traffic) but doesn't know how they got an IP address. So it assumes they have configured their own address statically.

EDIT: This applies to older routers like the RT-AC68U where the DHCP leases are stored in RAM. Newer HND routers don't suffer from this as much (at all?) because the DHCP leases are stored in non-volatile memory.

So the first question is are these devices indirectly connected to the router?
 
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"
Change the password(s).
"Thanks, but this will not clear the statics that are currently logged (some wired).

I get what you are saying, but the passwords have been changed since having the girls live here, and being the hub of activity for all the friends. They are grown now, and come home on the holidays. Now I just have the issue when they come home. I would also like to have my router do what I ask it to do...not what it chooses
 
The client list can be misleading or downright wrong. Particularly items marked as static, which tends to indicate a device on the network that isn't known in DHCP and isn't wirelessly connected to the router (therefore it assumes it's static). Note that "static" is not the same as "manual".

A classic example of this is a device connected indirectly to the router via a switch or access point. If the router is rebooted it looses it's list of DHCP assigned devices. However, clients that are indirectly connected do not detect that the router has restarted (their network interface remains up) so there is no reason for them to reacquire a DHCP lease. After the reboot the router can see they are on the network (because of their ARP traffic) but doesn't know how they got an IP address. So it assumes they have configured their own address statically.

So the first question is are these devices indirectly connected to the router?

Thank you

All are connected via a switch, directly wired to the router. Some have a secondary switch located in the room with the device (ex: my wife's office has PC, Printer, VOIP phone system, Living room also has secondary switch for ShieldTV, Smart ROKU TV, Xbox One) Some are connected via a wired AP (which, I know, halves the speed...but it's the solution I have).

I prefer wired where I can, for stability.

So, should I put all devices down when I attempt to clear the list?
 
So, should I put all devices down when I attempt to clear the list?
If you power cycle the switches/AP, or reboot the clients it should force them to initiate a new DHCP request. I suspect that many of the devices currently classified as static will change to DHCP.

If that doesn't fix it I suggest you power off the router and all the switches/AP. Then turn on the router and wait a couple of minutes for it to fully boot up. Then lastly power the switches/AP back on.
 
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I am not sure if it was mentioned:
Static assignment means the IP settings are manually made in that client device, these addresses shall not be in the DHCP range (in your case below 120). In my situation only a RT-AC1900U set a Media Bridge does have a Static IP address.
Manual assignment means the IP settings are defined by you in the Router DHCP Server and assigned by the DHCP Server (your Router) to the client device, these IP addresses will be in the DHCP range. From administrative point of view this is preferred for most client devices you want to have a fixed address, like printers or media servers.

If your DHCP range is set to start at 120, I do see many client devices that illegally have a Static address set in the client device it self which are in the DHCP range (above 120). This will bring the DHCP server in trouble.

As already said:
You are the one who can identify the devices in your house hold which should be connected (wired or wireless and direct or via additional switches or repeaters) to the router.
There is a Wireless Log that helps you accurately to see what client devices are connected wireless, changing the WiFi password can assist you to physically find those devices (to change the password, or someone start to complain the device does not have Internet).
For wired client devices you need to power down equipment or pull cables and see what device will disappear from the list (you maybe better use Ping to see their network response).
 
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Manual assignment means the IP settings are defined by you in the Router DHCP Server and assigned by the DHCP Server (your Router) to the client device, these IP addresses will be in the DHCP range. From administrative point of view this is preferred for most client devices you want to have a fixed address, like printers or media servers.
There is no requirement for manually assigned IPs to be within the DHCP range. The only requirement is that they are in the same subnet.
 
What wouterv says re Static vs Manual assignment is interesting, but it maybe a terminology specific to Asus? For what it's worth my understanding is the reverse. A static mapping is made on the DHCP server, in my case pfsense. If I want to assign a static mapping to a device that's been automatically assigned an IP, then I select 'add static mapping' under DHCP Leases - pfsense then notes that device's MAC address and opens a page where I can manually input my chosen IP address - this would be an address outside the primary DHCP pool. From then on that MAC address is linked in a table to that IP address - this being the meaning of 'static'. Renew the DHCP lease on either the device or restart the DHCP server and it gets allocated the chosen static IP indefinitely - the client device has no 'say' in the matter!

By contrast on a client device the only time I've set up manual IP addresses is where I want to connect two PC's directly or via a dumb switch without a dedicated DHCP server, when I might manually assign something like 10.0.0.1 to one PC and 10.0.0.2 to the other in their network settings and if they're both on the same subnet mask they should 'talk' to one another.

Having used Asus routers for years prior to moving to pfsense I had a fairly steep learning curve on network fundamentals and was a bit surprised (though it makes sense) to learn that I couldn't just make an automatically assigned IP into a static mapping in the sense of retaining the same IP address. The whole notion that there would be a range or pool from which DHCP addresses would be assigned with static IP's only being available outside of that pool was a new concept. My point is that it turns out I had been doing it "wrong" for many years - but since it seemed to work perfectly well, it can't have been all that wrong, at least as far as those specific Asus routers were concerned!
 
What wouterv says re Static vs Manual assignment is interesting, but it maybe a terminology specific to Asus?
No it's not specific to Asus. An IP address that is manually set on the client is almost universally called a static address. The problem comes when referring to addresses handed out by a DHCP server. An address that is reserved in DHCP for a particular client is called different things by different manufacturers. Microsoft calls them reservations and they are contained within a scope. Asus calls them manually assigned. pfSense (apparently ;)) calls them a static mapping. Netgear home routers IIRC calls them static addresses.

Personally I prefer to use the Microsoft terminology (unless referring specifically to the Asus GUI options) because it's unambiguous, and it's also what I'm used to.
 
Thank you all for the assistance, and insight. I just ran through a quick shutdown of the AP's and the mini switches in the two rooms. Some dropped off "static" but a couple are still there. I will power down all devices and switches this weekend (while my wife doesn't have her work stuff running), and mess with it then.

Until my network grew out of control, I had everything mapped...and static IP's assigned to wired devices on the client side, as it worked better to keep up on which device is in each location. As a gamer, Xbox was a little easier to control with a static IP. Then in 2013, when Xbox One allowed ipv6...I found that it was less hassle for NAT to have the DHCP assign the IP (that, and I have no clue how to manually assign ipv6).

Is there a download-able "network map" out there? I used to love the one built in to Win 7, super handy...and I could tell at a glance what was attached...
 
Is there a download-able "network map" out there? I used to love the one built in to Win 7, super handy...and I could tell at a glance what was attached...

If you mean one that does it for you I'd love to know the answer too!
I recently got a Unifi 6 Pro AP and there's a topology chart that shows you what's connected to the AP and then you can drill down per device to see which Wifi SSID or VLAN it's connected to. It's the only Ubiquiti / Unifi device I own but I assume that if you also had their switches and router then it would map out the whole network for you. Be great if more network gear did the same, but my network is a mish mash of different gear.
I've found draw.io quite useful to map things manually. Though practically I find spreadsheets more practically useful.
 
What wouterv says re Static vs Manual assignment is interesting, but it maybe a terminology specific to Asus?
...
I referred to the Asus terminology, like from my router:
1705135575700.png

RT-AC1900U: IP address manual set by me in the RT-AC1900U Media Bridge.
Printer1: IP address set by the Router DHCP Server as assigned by me.
MSFT 5 0: IP address automatically assigned by the Router DHCP Server.
 
Update:

All seems to be cleared now, IP's that were created static, read as static. DHCP assignments now read as DHCP. Some are showing up correctly with correct labels now, but there was a firmware update...so not really sure that was from clearing the network.
Now to the task of finding all devices (which I should have done when powering devices on, and logged them as they came on the network). I was able to name a few, but when I re-label them within the router interface, the new name may or may not stick... >sigh<

Marked as "Solved"

Thank you everyone
 
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