Hi,
my network dropped sometimes. So I looked into my routers logs and found nothing than:
DHCP Offering Lease Without Success
After reading almost everything about this topic on the internet there was no solution or reason assumable how to fix my instable network. So I started my dig and found that my network was flooded(~100-250 per sec) with alot of these kind of packets:
bridge 23.899 82 ← x x 192.168.128.134:68 (bootpc) 192.168.80.99:67 (bootps) ip:udp 350 1
my network is a 192.168.128.0/24 so why these 192.168.80.x?
So i searched and found that on my bridge interface are more ip-addresses bound the 192.168.128.2 and 192.168.80.99, my dhcp configuration looked like this:
add address-pool=pool128 allow-dual-stack-queue=no conflict-detection=yes interface=bridge lease-time=10m name=dhcp128
and the network is:
add address=192.168.128.0/24 dns-server=192.168.128.2 domain=mam-hh.adviser.com gateway=192.168.128.1 netmask=24 ntp-server=
192.168.128.2,192.168.128.1
so why are my clients asking the 192.168.80.99 for a “refresh” nr. The answer is simple the dhcp server uses the hostid 192.168.80.99 and also the response packet was send from 192.168.80.99 to 192.168.128.x.
This is some kind of odd – i would expect that the dhcp-server should use the nears ip as src address. But to fix this i just remove the 192.168.80.99 and now my dhcp-server behaviours like expected.
But my instable network seams not to be fixed. And most of my IoT Devices still asking 192.168.80.99 for a dhcp-refresh. I thought this will go await after some time so i waited 2 days nothing changed.
And the only way to fix this is to reboot any of this IoT devices, which is not easy if you have 120 esp’s in your network form esphomes over shellybulbs alot build directly in walls … and some epson printers.
It looks like that this persitance of the wrong ip-address to refresh dhcp is a problem to ESP32 and ESP8266 devices.
After I rebooted all devices it looks like that my instable network is gone.
Yes the ESP implementation has to befixed but to prevent such a sitatuation i would be nice if mikrotik searches the nearest src address in the dhcp-server implementation.
sorry for long story but to find this i took me almost 4 weeks.
meno
P.S. Used:
model: RB4011iGS+5HacQ2HnD
upgrade-firmware: 7.11
and
model: CRS326-24G-2S+
upgrade-firmware: 7.11