DHCP only on WiFi

RouterOS Beginner Basics
1

Hi all
.
I am a complete beginner to the networking. I would need your help with something.
In our company we have loads of hAP ac lite routers which will be put in the trucks with loads of equipment in different subnets.

The router would have to run DHCP on WiFi interface and on one of the LAN ports (it doesn’t matter which one), port 1 would have to be configured as standard “Internet” port. Then the tricky part is that the remaining three ports would also have to be in the same Bridge (I presume) but DHCP MUST NOT be running on them. Reason being is if someone plugs in other networks the DHCP from that router would create a mess.

I know how to create a bridge for all the ports and how to apply DHCP to it. I also know how to create port 1 as “Internet” port and enable NAT rule, I have no idea on how to disable DHCP on only specific ports - if that is even possible.
I was playing around with some filtering of UDP ports 67/68 but with no success.

I hope the above makes sense and what I want is even possible and you guys can help me.

Cheers,
Gasper

2

Totally understandable application.

I’d say this would work:

/interface list
add name=nodhcpports
/interface list member
add interface=ether3 list=nodhcpports
add interface=ether4 list=nodhcpports

/interface bridge filter
add action=log chain=input dst-port=67-68 in-bridge=bridge1 in-interface-list=nodhcpports ip-protocol=udp mac-protocol=ip src-port=67-68

-Chris

3

Hi Chris,
Thanks! This seems to do the trick. I did have to change action=log to action=drop.

I have two more sub questions here:

  1. I have one PC and one phone both running DHCP IP allocation and then the third PC with fixed IP connected to the filtered port. The PC with fixed IP can ping both other units, but the other way around is not working. So I can’t ping PC with fixed IP with none of the units using DHCP.
  2. Somehow connected to the previous question is also probably the fact that I don’t have internet connectivity through the port 1 on the PC with fixed IP, phone and other PC are working just fine.

Any ideas?

Oh wait…does this has something to do with me changing action to drop?

Many thanks,
Gasper