Hello - I was hoping there are some networking gurus here who can help me!
I have a Tesla Powerwall that has a wifi and ethernet interface. I had static IP addresses allocated to both but somehow my ATT Fiber modem lost all DHCP allocations and I had to redo them. Luckily, most of the devices grabbed the original IP address and I was able to fix others. However, I think I inadvertently allocated 2 static IP to the same network interface (wifi) on my Powerwall. When I do a LAN scan, I see the same MAC address with two different IP addresses (portion of the MAC address hidden).
The two static IP addresses (.123 and .130) do not show up as allocable (free) in the DHCP settings, but since I don't see the .123 in the IP allocation table, there appears to be no way to disassociate it from the incorrect MAC address. The MAC address for the ethernet interface does show up in the device list in the modem, but it has IP address as "pending".
Any suggestions on what I can do (apart from completely resetting the modem)?
FYI terminology wise, addresses that are handed out by DHCP, but are explicitly set for a given MAC are referred to as "fixed" addresses rather than "static" addresses. Static addresses are those set on the physical device with no DHCP involvement.
Most likely explanation is that the 123 address had been given to the device by the DHCP server, and the lease is still active. Until the lease times out, it will be unavailable for allocation. How long this may be depends upon the lease time setting in the DHCP server. It can be minutes to days, but 8-24 hours is common. It may be configurable in the modem, but changing the value now will not affect leases that have already been granted.
@rakeshg - it certainly is configurable, if you have the same fiber modem/router that I have (BGW320). And I think it can be set for as short as a few minutes. As @dennypage said, changing it now won't remove the existing allocation. But power-cycling the modem might do so.
It shouldn't. When the DHCP server comes up, it should retain the prior lease database state. Also, the client would claim the address when it sends its refresh.
Yes - that’s the one I have, but isn’t that a universal setting?
I don’t see the .123 address in the allocation table at all. (I see all the others - fixed as well as those allocated by DHCP from the pool). I only see the that particular IP when I do a LAN scan and also in the device list of the modem.
I’m wondering if I remove the DHCP reservation for the .130 address, the MAC will then show the .123 (if I do have a double DHCP reservation for that MAC) . Worst case scenario, I can restart the modem and that causes it to clear up (but based on what @dennypage says that may not work).
Will have to find a quiet time to try this in case it screws everything up!
Given that it's not a current fixed assignment, and it's not in the pool range, I would not expect it to appear in either place. Is there another place where "active" allocations are shown?
One other thing occurs. I've not used LANscan, and something that isn't clear is how LANscan is determining what MAC is associated with the IP addresses. Is it arping? If so, are all the replies coming from the Powerwall? Or are some coming from the router or another entity in the network?
Have you confirmed any of the LANscan info directly with a computer? Can you ping both addresses? If so, what shows in your local arp table after doing so?
I think the point is to avoid the term “static” since that has a specific meaning, without having to say “manual allocation” or “DHCP reservation” every single time while discussing the topic. That’s a lot of extra syllables to spit out.
FWIW the term “fixed” is used by Ubiquiti in the UniFi OS environment:
I suppose that's why it's shortened to "reserved" in conversation. The problem with "fixed" is that it has no widely understood association with DHCP, so can be taken to simply mean an address which isn't expected to change - static or reserved.
Although, if one wants to avoid ambiguity, neither static or reserved is correct - both are used pretty loosely. For instance, "static assignment" is what the popular dnsmasq server calls a manual assignment. Infoblox uses "reserved" to refer to addresses which are not handed out at all, but kept for future use. If you Google "fixed ip address" (with the quotes), you'll find stuff like "A static IP address, or fixed IP address, is an IP address that never changes", where static and fixed are considered the same thing.
That's why, if the distinction was important, I'd make it unambiguous by "spitting out those extra syllables" - "manually configured" vs. "DHCP dynamically assigned" or some such. But, "static" and "reserved" are, by far, the most widely used terms in my experience, across a wide range of enterprise customers.
Oh, a prosumer manufacturer like Ubiquiti is hardly an authoritative source for anything. If you want to go there, MikroTik uses "static lease".
While 35-40 years ago I would have greatly enjoyed having a vigorous discussion about the correctness of various networking terms, I've aged to the point of not caring so much.
You may not agree, but in the context of this thread, I believe "fixed" is the best choice. One need look no further than the original post, wherein the user's AT&T router refers to it as a "Fixed Allocation."
One can tell that from your first post, where you felt the need to pedantically "correct" the OP when it was perfectly clear what he was referring to, and to now continue responding while couching it as the last word.
I think the correct term in this thread is "static", because that's what the OP used and anyone knowledgeable knew what he was referring to. And no, "static" does not have a specific defined meaning, it's just somewhat common usage. See usage in dnsmasq and MikroTik. Heck, even Cisco refers to static DHCP.
Honestly i think the idea of trying to lock this down to words Static vs reservation vs fixed is a bit silly. Those are descriptive, and do not explain what the technology involved really is.
In the example I provided above it calls out as being a part of DHCP IP. I would imagine in the Ubilquiti ui you are setting that value somewhere in the DHCP settings.
Or possibly that is set at the connected device level. If that is the case it makes since as you are setting that connected device to a fixed ip address. But then one could also argue to use the term PIN as that is another option used for the Google Home device page.
Context is important and especially so when using descriptive terms.
Not sure if this semantic discussion of fixed vs static serves any purpose beyond reiterating our credentials as diehard nerds. And, as @danabw points out, we are the nerdiest community already
. Worst case scenario, I can restart the modem and that causes it to clear up (but based on what 
