Hostnames in network overview

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1

RPi 4B
RPiOS Bullseye

  • Pi-hole [v5.17.1]
  • FTL [v5.23]
  • Web Interface [v5.20.1]
    DHCP provided by Pi-hole

In the network overview I have a device with the wrong hostname. On the DHCP tab it shows the devices hostname is unknown. In the network overview it shows the device - my mobile phone has the hostname of a desktop.
When I click on the IP address of the device in the network overview I get the queries I expect from a phone. When I click on the hostname I get the queries from the desktop.

Wheredoes the network overview get its hostnames from.

Debug Token: tqjre0y7

2

Wheredoes the network overview get its hostnames from.

It uses the servers local arp cache. Checking network connections with arp and ip neigh | Network World

It seems like you have multiple DHCP servers on your network segment along with Pi-hole.

3

2 Pi-holes with non-overlapping DHCP scopes. The other pihole has a configured delay on its DHCP responce so it only gets used when my main pihole is down.

4

arp -a here does not give a hostname - each line begins with a ? instead of the hostname

5

How about the other approach with ip neigh?

And can you provide some of the output?

6

arp -a
? (192.168.0.153) at 00:fc:8b:50:b5:cf [ether] on eth0
? (192.168.0.203) at 00:d8:61:9e:b0:ac [ether] on eth0
? (192.168.0.71) at b8:27:eb:c0:4f:12 [ether] on eth0
? (192.168.0.158) at 68:b6:91:04:5f:36 [ether] on eth0
? (192.168.0.150) at c8:6c:3d:63:4f:f5 [ether] on eth0
? (192.168.0.76) at 00:0b:82:fd:f7:6c [ether] on eth0
? (192.168.0.167) at 90:73:5a:52:db:51 [ether] on eth0
? (192.168.0.217) at c8:02:10:7e:81:fe [ether] on eth0
? (192.168.0.201) at 00:1e:0b:82:5b:0d [ether] on eth0
? (192.168.0.164) at 08:cc:27:71:f9:7c [ether] on eth0
? (192.168.0.112) at bc:cf:4f:fd:f1:e9 [ether] on eth0
? (192.168.0.1) at 44:05:3f:7f:b2:d7 [ether] on eth0
? (192.168.0.204) at 68:b6:91:04:5f:36 [ether] on eth0
? (192.168.0.163) at on eth0
? (192.168.0.205) at 08:eb:74:9d:ad:04 [ether] on eth0
? (192.168.0.111) at d8:38:0d:01:a9:d0 [ether] on eth0
? (192.168.0.161) at on eth0
ip nei
192.168.0.153 dev eth0 lladdr 00:fc:8b:50:b5:cf STALE
192.168.0.203 dev eth0 lladdr 00:d8:61:9e:b0:ac REACHABLE
192.168.0.71 dev eth0 lladdr b8:27:eb:c0:4f:12 STALE
192.168.0.158 dev eth0 lladdr 68:b6:91:04:5f:36 DELAY
192.168.0.150 dev eth0 lladdr c8:6c:3d:63:4f:f5 STALE
192.168.0.76 dev eth0 lladdr 00:0b:82:fd:f7:6c REACHABLE
192.168.0.167 dev eth0 lladdr 90:73:5a:52:db:51 STALE
192.168.0.217 dev eth0 lladdr c8:02:10:7e:81:fe STALE
192.168.0.201 dev eth0 lladdr 00:1e:0b:82:5b:0d STALE
192.168.0.164 dev eth0 lladdr 08:cc:27:71:f9:7c STALE
192.168.0.112 dev eth0 lladdr bc:cf:4f:fd:f1:e9 STALE
192.168.0.1 dev eth0 lladdr 44:05:3f:7f:b2:d7 REACHABLE
192.168.0.204 dev eth0 lladdr 68:b6:91:04:5f:36 STALE
192.168.0.163 dev eth0 FAILED
192.168.0.205 dev eth0 lladdr 08:eb:74:9d:ad:04 STALE
192.168.0.111 dev eth0 lladdr d8:38:0d:01:a9:d0 STALE
192.168.0.161 dev eth0 FAILED

7

Have you tried flushing the network table, under Settings > System > Flush network table?

8

Yes it is still there. I am sure i have also deleted the device and it has returned with the wrong hostname

9

Hi @Moto were you able to fix this? I found in the past when this happens I can reset the correct hostname by doing a PTR query against its IP.

For a single IP this command will do it (adjust IP as needed):

dig -x 192.168.1.55

Or to fix a whole network, since nmap does a PTR lookup during host discovery, this command will do all active IPs (adjust network as needed):

nmap -sn 192.168.1.0/24

You can see the PTR requests in the Query Log, at which point Pi-hole has the correct hostnames.

Curious to know if this works for you.

10

I deleted the device and ran nmap -sn 192.168.0.0/24 and it reappeared without the wrong hostname. Seconds later it was showing the wrong hostname so it didn't work.

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11

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