HA unconventional network setup

Installation Home Assistant OS
1

Hello, I would like some feedback about my HA LAN setup please.

The home setup is:
0 routers
1 computer with no DHCP server
1 phone for hotspot Internet
1 AP (UAP-AC-Lite)
3 home automation WLAN devices (no cloud)

The computer’s Wi-Fi connects to the phone hotspot.
I think the computer’s IP is DHCP and is leased from the phone hotspot?
The AP is Ethernet connected to the computer RJ45 port.
The AP is controlled from the computer UniFi controller.
The UniFi controller sees the AP but cannot adopt the AP.
The AP expects a DHCP server to lease an IP, however there is no DHCP server, so the AP defaults to 192.168.1.20.

I would like to set the computer to a preferred static IP.
I would like to set the AP to a preferred static IP.
I’m unsure how as there’s no gateway.
I don’t think installing a DHCP sever dnsmasq is needed, as I want static IPs.
HA is installed on the computer’s VM.
Here’s the computer Terminal output:

raspberrypi5@raspberrypi:~ $ ip -c a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 2c:cf:67:13:a3:da brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 2c:cf:67:13:a3:db brd ff:ff:ff:ff:ff:ff
    inet 172.20.10.9/28 brd 172.20.10.15 scope global dynamic noprefixroute wlan0
       valid_lft 83622sec preferred_lft 83622sec
    inet6 fe80::2845:ad69:3e36:5fa2/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
raspberrypi5@raspberrypi:~ $ dnsmasq --test
dnsmasq: syntax check OK
2

You must ssh into AP and set inform address. User/pass is likely ubnt/ubnt. After login the command “help” and “info” will give hint to how to do this. Also google it.

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3

Your mobile hotspot is likely a router/gateway too.
Look into the settings for the mobile hotspot and make sure you use those to set up static IPs on the devices.

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4

Really best method would be to setup firewall on PC and use it is dhcp/gateway/dns. It would be great. And device side static IP would be unnecessary. You could also have vlan in this case.

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5

That would require the computer to always be on or the DHCP requests would fail when it is shutdown/in sleep.

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6

Thanks tmjpugh, that helps with the AP static IP configuration of say:
IP 192.168.1.240
Gateway: ? unsure for now.

The AP static IP of 192.168.1.240 means I will need to set the computer to 192.168.1.098 perhaps? Unsure for now what to set the computer’s gateway to as well.

Then I would not be surprised if the phone hotspot fails to connect to the computer’s static IP 192.168.1.098 (gateway undecided if needed or what it will be).

Why would a DHCP server be the best method? I would like the computer and AP to have static IPs and perhaps also the WLAN devices if that’s possible. The static IPs would enable configuration and better access to management.

VLANs have always confused me, how would a VLAN help?

Thanks WallyR.
The phone hotspot settings are not what I want on the computer’s static IP.
Currently the computer’s IP which seems to be derived from the phone’s hotspot is: inet 172.20.10.9/28 brd 172.20.10.15.
I would like the computer to have 192.168.1.098 and unsure if or what the gateway needs to be.

DHCP leases remain on the DHCP leased WLAN device, until the WLAN device is shutdown. The DHCP server (which would be dnsmasq running on the computer) being shut down would not affect the DHCP leased WLAN device, as the WLAN device has already been served a DHCP.

8
  1. In order for 2 devices to talk they need to be physically connected together and belong to the same subnet.
  2. You do not need to configure a gateway for 2 devices to talk locally
  3. A DHCP server is just a piece of software installed on a computer that assigns IP address to other PCs connected to the same network. To set it up you would configure a static IP address on the PC the DHCP Server will run on like 192.168.1.1. Then you would create a scope which is the range of address the DHCP server will hand out to other devices. EX: 192.168.1.2 to 192.168.1.100. Then you connect the devices to your network and they automatically get assigned an unused IP from your scope.
  4. Almost all smart devices can only obtain an IP through DHCP this is why you need a DHCP server.
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9

Your AP is the part that provide WiFi to your devices.
All devices should there be either connected as WiFi clients or wired with a physical cable to this part.

The problem here is the phone.
When it is running as a mobile hotspot, then it does the same as the AP, then which is often called hotspot mode. Two devices running in hotspot mode will not be able to connect to each other, so you are in a kind of hard place here.

Regarding DHCP, then the DHCP lease have to be renewed before the lease time runs out and if. A device restarts then it will request a new lease of an IP address too, so you need a DHCP running if you are using dynamically assigned IP addresses. If all devices are using static IP addresses, then a DHCP server is not needed.

Talking about IP networks and subnet masks makes no sense until you get the network connections issue above solved.
This might be possible if the phone can provide the internet over the USB cable and the computer then shares this connection to the rest of the devices or the phone can be replaced with a mobile broadband router which should have ethernet ports that can be wired to the AP.