Hi,
I have two ISPs connected to my router, BigCable and BigTelco(DSL). BigCable is my primary ISP with BigTelco as my backup. This worked flawlessly, until I upgraded my cable modem.
The new cable modem has an internal DHCP server that will hand the router an 192.168.100.0/24 (usually .10) address (guess for modem setup for new installations).
/ip dhcp-client print terse output:
0 comment=defconf interface=ether1 add-default-route=yes default-route-distance=1 use-peer-dns=no use-peer-ntp=no dhcp-options=hostname,clientid status=bound address=192.168.100.10/24 gateway=192.168.100.1 dhcp-server=192.168.100.1 expires-after=24s
My routing filter rule detects a gateway ping and puts BigCable at the top of my routing table (distance 1).
/routing filter add chain=dynamic-in distance=1 prefix=0.0.0.0 prefix-length=0 set-check-gateway=ping set-route-comment=BigCable
This state leaves my network without internet access until BigCable fixes their end and the cable internet is backup, then I get the following:
0 comment=defconf interface=ether1 add-default-route=yes default-route-distance=1 use-peer-dns=no use-peer-ntp=no dhcp-options=hostname,clientid status=bound address=realinternetaddress/22 gateway=realinternetgatewayaddress dhcp-server=realinternetaddress primary-dns=realinternetaddress secondary-dns=realinternetaddress expires-after=2d23h4m57s
So, the modem is passing through DHCP from BigCable, when BigCable outage is over.
I tried blocking the 192.168.x.x DHCP from the modem with the following fw rule:
add action=drop chain=input comment=\
"drop dhcp from modem that is not from bigcable" in-interface=ether1 \
protocol=udp src-address=192.168.100.0/24 src-port=67-68
But, no luck.
What am I missing here?
Thanks.