DHCP - unknown devices on network - running out of IP - can't assign new range

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1

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Expected Behaviour:

Hi - I assigned a range of 50 IP addresses. I thought more than enough. It seems I have run out with my printer complaining the same IP exists when I turn it on. Looking at the DHCP assignments, I have assigned them all! But in fact, there are at least 20 with hostname 'unknown' so assume should be removed or cleared out somehow.

Actual Behaviour:

When I go to extend the range, i get an error.
To IP (192.168.1.275) is invalid!

How can I remove old / dead assignments, flush or extend the range?

Debug Token:

[✓] Your debug token is: https://tricorder.pi-hole.net/zon8fdvv8q

Thanks,
Brett

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You can extend the range downward, but can't go above 255. You currently have the following range set as follows:

    DHCP_ACTIVE=true
    DHCP_START=192.168.1.205
    DHCP_END=192.168.1.255

Change this to DHCP_START=192.168.0.155 and you will have 100 IP addresses in the range.

1 Like
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oh, ok, thanks! is there a way to flush out those unknown devices? I assume old if i had to reset my network or something..?

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With your lease duration of 24 hours, any old leases will expire after that time and the IP's become available again.

DHCP_LEASETIME=24

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Is that if a device doesn't try to connect or is not active I guess?
I still have a heap of devices in my network showing 'unknown'. In particular, my main tv is a TCL Roku TV - according to my router - and the DHCP list in pihole, it has an IP address. But the TV will now no longer connect. In settings on TV it doesn't seem to have an IP address even after restart of TV. All other devices on the network seem to be working OK.

Not sure how to fix/solve.

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If the TV does not have an IP according to it at least, it should not have been active and that IP should have been released. (I guess). The TV is giving error code 009 - it is on my wireless network says signal strength is excellent - but does not report an IP address. Assume something to do with pi.hole since pi.hole is my DHCP server.

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[✓] Your debug token is: https://tricorder.pi-hole.net/tyytom6exr

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You can look in the pihole log at /var/log/pihole.log , and this will show all the DHCP transactions. You can tail this log with pihole -t

Start tailing the log, then turn on the TV and see if there are any DHCP transactions started. DHCP_OFFER, etc.

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Are either of these queries from the TV?

   Apr 24 00:00:31 dnsmasq[756]: query[A] scribe.logs.roku.com from 192.168.1.220
   Apr 24 00:00:31 dnsmasq[756]: /etc/pihole/gravity.list scribe.logs.roku.com is 0.0.0.0
  
   Apr 24 00:00:41 dnsmasq[756]: query[A] scribe.logs.roku.com from 192.168.1.205
   Apr 24 00:00:41 dnsmasq[756]: /etc/pihole/gravity.list scribe.logs.roku.com is 0.0.0.0
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https://appuals.com/error-code-009-roku/

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02:56:58 dnsmasq-dhcp[1750]: DHCPREQUEST(wlan0) 192.168.1.207 44:d8:78:80:cc:e4

02:56:58 dnsmasq-dhcp[1750]: DHCPACK(wlan0) 192.168.1.207 44:d8:78:80:cc:e4

this showed up when doing a connection check.

2:59:17 dnsmasq-dhcp[1750]: DHCPREQUEST(wlan0) 192.168.1.207 44:d8:78:80:cc:e4

02:59:17 dnsmasq-dhcp[1750]: DHCPACK(wlan0) 192.168.1.207 44:d8:78:80:cc:e4

similar on reboot

this is the TV as I know.

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The DHCP service of Pi-hole is not provided by the Pi-hole code, but is provided by the underlying dnsmasq. I would visit some of the dnsmasq or Roku forums to see if there is any discussion of this issue. I'm not very conversant in DHCP.

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You could assign an IP to that MAC address via dhcp reservation in the /admin/ interface.
Looks like the device is asking for an IP, the dhcp server provides it ... but then something happens ...

No manual IP settings in the tv (as a last resort)?

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I don't think I can assign an IP on the TV.
Now i can't seem to get to the web interface admin using pi.hole. Have to use the IP address!

But I wonder if it's the TV. Only device on the network not working. Was fine - wonder if it had a SW update or something.. I put my router back to settings before adding pi-hole - pointed dns somewhere, and had it do the DHCP (with Orbi, pi-hole only seems to working having p-ihole also do the DHCP). Anyway, most devices on my network got a new IP address including the TV at least according to the router. But the TV is still not connected. Will try to completely turn off the Raspberry Pi next and re-test. Other roku devices on my network do work, but are not roku tvs - they're roku sticks.

Brett

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Hi, I have a similar problem with an android tablet, which changes mac address every time it connects to wifi. If I don't leave wifi always on (to save battery power) it quickly saturates the 250 available IPs on my LAN.
On reddit I found a post where is suggested to remove /etc/pihole/dhcp.leases, and restart DHCP daemon, but this does not seems to work. Where are leases stored currently on Pi hole 4.4 / FTL 4.3.1?

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In that exact file:

pi@noads:~ $ date && stat /etc/pihole/dhcp.leases
Wed 29 Apr 21:53:41 CEST 2020
[..]
Modify: 2020-04-29 19:18:43.269745306 +0200
[..]

How did you restart ?
If configure Pi-hole to do DHCP, the pihole-FTL daemon does DHCP:

sudo service pihole-FTL reload

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What's that device's name?

If that device changes its MAC address ever so often, does it perhaps claim a consistent name for itself?

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Set the lease time to 1h and that should tace care of old unused entries.

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So, turns out my dumb router by itself / not me! started blocking the TV, both wired and wireless interfaces (i have access control on). I forgot about checking access control on the router :(.

Now though, my Pi doesn't seem to have working DNS. I can ping a name server, like 8.8.8.8 but not yahoo.com. I am not using Pihole at the moment as router is back to normal settings. Maybe I'll uninstall Pihole and start again.

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