Client receives a "Network is unreachable" error when attempting to send DHCP packets

Mathias1 · May 17, 2024, 2:33pm

Expected Behaviour:

Pi-hole should assign IPv4 addresses to all devices via DHCP without any issues. Devices should be able to obtain an IP address and connect to the internet seamlessly.

Operating System: Ubuntu 22.04
Hardware: x86_64

Steps Taken:

Release and Renew DHCP Lease:

sudo dhclient -r wlp2s0
sudo dhclient wlp2s0

Manually Assign Static IP:

sudo ifconfig wlp2s0 192.168.0.50 netmask 255.255.255.0 up
sudo route add default gw 192.168.0.1

Restart Network Services on Pi-hole:

sudo systemctl restart pihole-FTL
sudo systemctl restart dnsmasq

Restart Network Manager on Client:

sudo systemctl restart NetworkManager
sudo ifdown wlp2s0 && sudo ifup wlp2s0

Actual Behaviour:

The Pi-hole DHCP server is enabled and correctly configured to offer IP addresses from 192.168.0.30 to 192.168.0.250.
The client receives a "Network is unreachable" error when attempting to send DHCP packets.
There are no firewall or SELinux rules blocking DHCP traffic.

Debug Token:

https://tricorder.pi-hole.net/Izt9QPxL/

jfb · May 17, 2024, 2:55pm

From your debug log and the information presented, this looks like a problem with that particular client, and not with Pi-hole.

Your Pi-hole is the DHCP server, and is answering service calls:

*** [ DIAGNOSING ]: Discovering active DHCP servers (takes 10 seconds)
   Scanning all your interfaces for DHCP servers
   Timeout: 10 seconds
   
   * Received 300 bytes from eth0:192.168.0.4
     Offered IP address: 192.168.0.91
     Server IP address: 192.168.0.4
     Relay-agent IP address: N/A
     BOOTP server: (empty)
     BOOTP file: (empty)
     DHCP options:
      Message type: DHCPOFFER (2)
      server-identifier: 192.168.0.4
      lease-time: 86400 ( 1d )
      renewal-time: 43200 ( 12h )
      rebinding-time: 75600 ( 21h )
      netmask: 255.255.255.0
      broadcast: 192.168.0.255
      dns-server: 192.168.0.4
      domain-name: "lan"
      router: 192.168.0.1
      --- end of options ---
   
   DHCP packets received on interface eth0: 1

If you assign a static IP on a client, that client won't request an IP from a DHCP server - you have told it what IP to use.

DHCP transactions are shown in the pihole.log at:

/var/log/pihole/pihole.log

Refresh the DHCP lease (after removing the static entry) on the client in question and then look in this log for the DHCP transactions from that client. Are any requests received? If so, what are the subsequent transactions (DHCPDISCOVER, DHCPOFFER , etc.)

sudo grep DHCP /var/log/pihole/pihole.log

Mathias1 · May 17, 2024, 3:08pm

May 17 17:04:39 dnsmasq-dhcp[13609]: DHCPNAK(eth0) 192.168.0.11 38:d5:7a:47:71:b9 address not available
May 17 17:04:42 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:04:42 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:04:42 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:04:42 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:04:46 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:04:46 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:04:54 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:04:54 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:05:14 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:05:14 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:05:36 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 38:d5:7a:47:71:b9 
May 17 17:05:36 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:05:37 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:05:37 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:05:39 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 38:d5:7a:47:71:b9 
May 17 17:05:39 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 17:05:40 dnsmasq-dhcp[13609]: DHCPDISCOVER(eth0) 192.168.0.11 38:d5:7a:47:71:b9 
May 17 17:05:40 dnsmasq-dhcp[13609]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9

i refreshed the dhcp lease and this is in the logs.

the client:

sata@5pro:~$ sudo tcpdump -i wlp2s0 port 67 or port 68
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on wlp2s0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
17:05:10.287641 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 288
17:05:34.517337 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 288
17:05:35.764804 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 300
17:05:36.517311 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 288
17:05:38.402216 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 300
17:05:39.378234 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 288
17:05:43.582466 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 288
17:05:46.959404 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 38:d5:7a:47:71:b9 (oui Unknown), length 300

jfb · May 17, 2024, 3:23pm

It appears that Pi-hole is making a DHCP offer but the client is not accepting it.

Compare this output to the transactions you see when you release/renew/refresh DHCP lease on a different client that is getting a DHCP lease.

Mathias1 · May 17, 2024, 5:08pm

logs with a new client:

May 17 19:07:01 dnsmasq[14662]: compile time options: IPv6 GNU-getopt no-DBus no-UBus no-i18n IDN DHCP DHCPv6 Lua TFTP no-conntrack ipset no-nftset auth cryptohash DNSSEC loop-detect inotify dumpfile
May 17 19:07:01 dnsmasq-dhcp[14662]: DHCP, IP range 192.168.0.20 -- 192.168.0.250, lease time 1d
May 17 19:07:06 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:06 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPREQUEST(eth0) 192.168.0.94 00:d8:61:59:6e:3e 
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPACK(eth0) 192.168.0.94 00:d8:61:59:6e:3e DESKTOP-L42VPPK
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:09 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:13 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:07:13 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:07:13 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:13 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:14 dnsmasq[14662]: DHCP 192.168.0.94 is DESKTOP-L42VPPK.lan
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:17 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:19 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:19 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:19 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:19 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:21 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:07:21 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:07:22 dnsmasq-dhcp[14662]: DHCPREQUEST(eth0) 192.168.0.99 22:51:72:4a:b4:96 
May 17 19:07:22 dnsmasq-dhcp[14662]: DHCPNAK(eth0) 192.168.0.99 22:51:72:4a:b4:96 wrong address
May 17 19:07:22 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:22 dnsmasq-dhcp[14662]: DHCPACK(eth0) 192.168.0.60 22:51:72:4a:b4:96 Pixel-7a
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPACK(eth0) 192.168.0.60 22:51:72:4a:b4:96 Pixel-7a
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:23 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:25 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:25 dnsmasq-dhcp[14662]: DHCPACK(eth0) 192.168.0.60 22:51:72:4a:b4:96 Pixel-7a
May 17 19:07:26 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:07:26 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:07:29 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:29 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.60 22:51:72:4a:b4:96 
May 17 19:07:30 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:07:30 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:07:31 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:31 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:31 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:31 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 38:d5:7a:47:71:b9 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:39 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.60 22:51:72:4a:b4:96 
May 17 19:07:43 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:43 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:46 dnsmasq-dhcp[14662]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:07:46 dnsmasq-dhcp[14662]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:07:48 dnsmasq[14778]: compile time options: IPv6 GNU-getopt no-DBus no-UBus no-i18n IDN DHCP DHCPv6 Lua TFTP no-conntrack ipset no-nftset auth cryptohash DNSSEC loop-detect inotify dumpfile
May 17 19:07:48 dnsmasq-dhcp[14778]: DHCP, IP range 192.168.0.20 -- 192.168.0.250, lease time 1d
May 17 19:07:51 dnsmasq[14778]: DHCP 192.168.0.94 is DESKTOP-L42VPPK.lan
May 17 19:07:54 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:07:54 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:07:58 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:07:58 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:07:58 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 22:51:72:4a:b4:96 
May 17 19:07:58 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.60 22:51:72:4a:b4:96 
May 17 19:08:01 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 38:d5:7a:47:71:b9 
May 17 19:08:01 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c6:1c 
May 17 19:08:04 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.198 48:55:19:d9:c6:1c 
May 17 19:08:08 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:d9:c8:1f 
May 17 19:08:08 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.191 48:55:19:d9:c8:1f 
May 17 19:08:09 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 48:55:19:db:28:68 
May 17 19:08:09 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.182 48:55:19:db:28:68 
May 17 19:08:09 dnsmasq[14778]: DHCP 192.168.0.60 is Pixel-7a.lan
May 17 19:08:10 dnsmasq[14778]: DHCP 192.168.0.94 is DESKTOP-L42VPPK.lan
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 38:d5:7a:47:71:b9 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.150 38:d5:7a:47:71:b9 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPDISCOVER(eth0) 60:74:f4:ae:ac:94 
May 17 19:08:13 dnsmasq-dhcp[14778]: DHCPOFFER(eth0) 192.168.0.155 60:74:f4:ae:ac:94

same thing happens. i think my gateway is blocking this for some reason.
i have a ZTE MC888A with standard config, except no DHCP enabled obviously.
I cant set the DNS to my pihole in the router settings apparently, there is no option for that.

DL6ER · May 17, 2024, 5:57pm

There are no issues with your DHCP server, but there seem to be issues with (at least) two of your clients. Let me answer the two distinct parts you have been asking here independently:

You said your range is 192.168.0.30 - 192.168.0.250

but you client is trying to renew a lease with address 192.168.0.11:

.11 is outside of the allowed range .30 - .250 so the lease renewal attempt is rightfully blocked as ... the address not available

Now the range has changed, but that's not an issue here.

This is a different error message, it means that the device with MAC 22:51:72:4a:b4:96 is known and tried to renew the wrong address (192.168.0.99) - however, this is not the address we know it has!

As it failed with renewing, the client thereafter rightfully requests a new lease:

This time it received the address we already know it should have had the whole time: 192.168.0.60

Mathias1 · May 17, 2024, 6:24pm

thank you for that clear response!

so for some reason on that client it worked, but still for all devices the dns lookup is not working.

my problematic device doesnt receive the ipv4 as it cant send the ack to the pihole:

sata@5pro:~$ ip addr
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 
       valid_lft forever preferred_lft forever
2: tailscale0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1280 qdisc fq_codel state UNKNOWN group default qlen 500
    link/none 
    inet 100.79.248.46/32 scope global tailscale0
       valid_lft forever preferred_lft forever
    inet6 fd7a:115c:a1e0:ab12:4843:cd96:624f:f82e/128 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::73be:d4d3:d23f:e2c7/64 scope link stable-privacy 
       valid_lft forever preferred_lft forever
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 38:d5:7a:47:71:b9 brd ff:ff:ff:ff:ff:ff
    inet6 2001:4bb8:191:6704:c71a:7bf2:2606:1e5b/64 scope global temporary dynamic 
       valid_lft 86364sec preferred_lft 14364sec
    inet6 2001:4bb8:191:6704:327a:3c20:59f0:b292/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 86364sec preferred_lft 14364sec
    inet6 fe80::117b:473b:3f21:2145/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
sata@5pro:~$ ping 192.168.0.11
ping: connect: Network is unreachable
sata@5pro:~$

DL6ER · May 18, 2024, 5:18am

From what it looks like to me, I wouldn't say your Pi-hole doesn't send the ACK, it's more the client does not receive it.

We have seen very similar behavior in the past with Google Nest and some other routers, may even be that ZTE was among those. The problem was that such routers often prevented forwarding DHCP/DNS packets and the solution has been to either replace the router altogether or buy a $15 WiFi router (eg TP-Link), put this one behind the existing router, and connect all devices to this new well-behaving router. If you maybe already have something like this available, it's surely worth a try.

Mathias1 · May 18, 2024, 11:43am

Thank you so much, I will give it a try and buy a new router.
It seems like the router blocks this traffic for some reason. I also talked to my ISP and he told me that this issue does occure on some ZTE routers.

system · June 8, 2024, 11:43am

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