Pihole unable to reach Gateway after reboot

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1

AS I WAS READY TO SUBMIT THIS TOPIC, I ran pihole -up, which previously had failed. This time it succeeded, and pihole is working again. I still don't know what resolve the problem though.

Expected Behaviour:

I restarted my router and 2 pihole servers after a planned power outage. I gracefully shutdown both the router and pihole servers before the outage. Since no settings were changed on my router or pihole servers, I expected to reach servers (eg, Google) as I did before the outage.
I am running Buster lite 4.19.97-v7+ on both a Raspberry Pi 3B and Pi Zero.

Actual Behaviour:

When power was restored to the router and pihole servers, I was not able to reach any servers outside of my own LAN. Initially I noted that my IPv6 had changed after running pihole -d, which I corrected. However, pihole -d shows that I cannot reach my gateway 192.168.0.1. However, I can successfully ping 192.168.0.1 from the command prompt.
I can also ping my pihole server 192.168.0.250 from my TP Link Archer AX50 router.

My static IP setting are:

interface eth0
static ip_address=192.168.0.250/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1
interface wlan0
static ip_address=192.168.0.249/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

ifconfig:

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.250 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 2601:645:4000:76:541b:4af2:37eb:5992 prefixlen 64 scopeid 0x0
inet6 fe80::167:78a:df19:42ee prefixlen 64 scopeid 0x20
ether b8:27:eb:96:cb:95 txqueuelen 1000 (Ethernet)
RX packets 4318 bytes 865969 (845.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1956 bytes 301513 (294.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 253 bytes 24002 (23.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 253 bytes 24002 (23.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.249 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::c123:c805:6bd6:4ff1 prefixlen 64 scopeid 0x20
inet6 2601:645:4000:76:d4fc:8c48:124a:9a8a prefixlen 64 scopeid 0x0
ether b8:27:eb:c3:9e:c0 txqueuelen 1000 (Ethernet)
RX packets 2415 bytes 594092 (580.1 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 104 bytes 12780 (12.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Debug Token:

https://tricorder.pi-hole.net/1jqqrc5om5

2

You have two interfaces connected to the same network with different IP's in the same subnet.
This most likely confuses the routing engine.
If want to connect both interfaces to the same subnet, better create a bridge interface with a single IP that aggregates/bridges both interfaces:

3

Thanks for the prompt reply....you were absolutely correct that the 2 pihole servers with different IPs running on the same network created the problem. I shut down one of the servers and pihole is working just fine with no errors when I run pihole -d.

Interestingly, I did remember having this problem with pihole version 4.

I want to create redundancy in my DNS servers, so I will try creating a bridge interface as you suggested.

4

@deHakkelaar was suggesting that your two NICs on one Pi-hole would probably interfere with routing, not your two Pi-holes.

Besides, you've only shown as the configuration for one of your RPis, likely the 3B. If you do not need wlan0 on your 3B, it may be easiest to just disable wifi on that device.

5

Apologies for my misunderstanding the suggested solution. I disabled wifi on both of my Raspberry Pi’s running pihole, and now the two DNS servers with different IPs work fine together on the same network using only Ethernet.

Thank you!!

6

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