Raspberry Pi DHCP & Pihole

[Harold Hartley]

I read an article earlier this month on software bugs and it had mention 
a bug in dhcp and that they were trying to fix it.

Not sure if it might be related to your problem. I wish I kept the 
article to pass on to others but I didn't.

Sorry about that.

On 3/26/22 12:04, AZ Pete via PLUG-discuss wrote:
> All,
> I ran into an interesting bug that I thought I'd share here. I set up 
> one of my Raspberry Pi computers as a Pi-hole and also configured it 
> to act as my DHCP server.
> After the Pi was acting as a my DHCP router I noticed hundreds of log 
> entries in the pihole.log file.
> The Pi was being flooded with these kind of requests:
>
> 10:17:10 dnsmasq-dhcp[20546]: DHCPINFORM(eth0) 192.168.1.41 
> dc:a6:32:65:89:d9
> 10:17:10 dnsmasq-dhcp[20546]: DHCPACK(eth0) 192.168.1.41 
> dc:a6:32:65:89:d9 desertpi
>
> Literally dozens of entries per second. As it turns out, I set my 
> other two PIs to static IP addresses using the GUI interface, which 
> put this into dhcpcd.conf file:
>     interface eth0
>     inform 192.168.1.41
>     static routers=192.168.1.1
>     static domain_name_servers=192.168.1.1
>
> When I changed it to this there were no more log entries as listed 
> above (i.e. changed 'inform' to 'static')
>         interface eth0
>         static ip_address=192.168.1.41/24
>         static routers=192.168.1.1
>         static domain_name_servers=192.168.1.1
>
> As it turns out there is a bug in dhcp that causes INFORM messages to 
> flood the router. Since my Netgear router acted as the dhcp server 
> previously, I never saw these entries (the netgear log must not 
> display them). But, I had always wondered why my PI's network LED was 
> always blinking so much....
>
> I could only find two article discussing this:
> https://raspberrypi.stackexchange.com/questions/116121/huge-syslog-filled-with-dhcpcd-lines
> https://forums.raspberrypi.com/viewtopic.php?t=265516
>
> My take away: Don't use the GUI to configure things. :)
>
> Hope this helps someone...
> Thanks,
> Peter
>
>
>
>
>
>
>
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-- 
Harold Hartley
17632 N. 5th Pl
Phoenix, AZ 85022
wheelie207 at ownmail.net
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