Unable to generate debug log

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1

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Expected Behaviour:

Trying to generate debug log : pihole -d

-operating system:

"Raspbian=9,10 Ubuntu=16,18,20 Debian=9,10 Fedora=32,33 CentOS=7,8"
[✓] Distro: Raspbian
[✓] Version: 10

Core version
[i] Core: v5.3.1

FTL version
[✓] FTL: v5.8.1

lighttpd version
[i] 1.4.53

php version
[i] 7.3.27

Actual Behaviour:

Trying to generate a debug log but it got stuck at " *** [ DIAGNOSING ]:Discovering active DHCP servers (takes 10 seconds) " for more than 3 hours

Using router's DHCP

2

Run on your Pi-hole host machine, what's the output of:

pihole-FTL dhcp-discover

ls -la /etc/dnsmasq.d/
3 
pihole-FTL dhcp-discover

User@raspberrypi:~ $ pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers
Timeout: 10 seconds

  • Received 300 bytes from eth0:192.168.1.1
    Offered IP address: 192.168.1.145
    Server IP address: 192.168.1.1
    Relay-agent IP address: N/A
    BOOTP server: (empty)
    BOOTP file: (empty)
    DHCP options:
    Message type: DHCPOFFER (2)
    server-identifier: 192.168.1.1
    lease-time: 93600 ( 1d 2h )
    renewal-time: 46800 ( 13h )
    rebinding-time: 81900 ( 22h 45m )
    netmask: 255.255.255.0
    broadcast: 192.168.1.255
    dns-server: 192.168.1.1
    router: 192.168.1.1
    --- end of options ---

  • Received 300 bytes from eth0:192.168.1.1
    DHCPOFFER XID (2711226360) does not match our DHCPDISCOVER XID (1884949425) - ignoring packet (not for us)

DHCP packets received on interface lo: 0

ls -la /etc/dnsmasq.d/

User@raspberrypi:~ $ ls -la /etc/dnsmasq.d/
total 20
drwxr-xr-x 2 root root 4096 Sep 2 20:31 .
drwxr-xr-x 120 root root 12288 Sep 2 20:31 ..
-rw-r--r-- 1 root root 1415 Sep 2 20:31 01-pihole.conf

4

We sometimes see DHCP discovery failing or aborting the log when illegal characters would appear in some of the DHCP options.

This doesn't seem to be the case for you, as your solitary dhcp-discover succeeded.

Just to be sure:
The DHCP discover output above seems to be missing a few lines towards the end - you wouldn't have redacted your output, would you?

5

after waiting for 1 hour, that's all i have

User@raspberrypi:~ $ pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers
Timeout: 10 seconds

Received 300 bytes from eth0:192.168.1.1
Offered IP address: 192.168.1.145
Server IP address: 192.168.1.1
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
server-identifier: 192.168.1.1
lease-time: 93600 ( 1d 2h )
renewal-time: 46800 ( 13h )
rebinding-time: 81900 ( 22h 45m )
netmask: 255.255.255.0
broadcast: 192.168.1.255
dns-server: 192.168.1.1
router: 192.168.1.1
--- end of options ---

Received 300 bytes from eth0:192.168.1.1
DHCPOFFER XID (2711226360) does not match our DHCPDISCOVER XID (1884949425) - ignoring packet (not for us)

DHCP packets received on interface lo: 0

6

A post was split to a new topic: Debug log problems

9

It seems you've indeed encountered a bug where dhcp-discover would fail to terminate under certain circumstances when clients use XIDs to request a DHCP lease. It's by far more common for clients to use their MAC to do so, which allowed that misbehaviour to escape proper attention - until you helped to find it.

Pi-hole's developers are already engaging in a fix.

12

Issue solved at this release:

13

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