Identify physical interface from DHCP client script

RouterOS General
1

I need to identify which physical interface within a bridge which issued a DHCP lease.

/interface bridge port
add bridge=LOCAL-Br interface=ether1
add bridge=LOCAL-Br interface=ether2
add bridge=LOCAL-Br interface=ether3
add bridge=LOCAL-Br interface=ether4
add bridge=LOCAL-Br interface=ether5
/interface vlan
add interface=LOCAL-Br name=VLAN2-WAN vlan-id=2

# This script logs the VLAN interface as one would expect, but I need to know which ethernet port it came from so that I can apply further configuration to the interface.

/ip dhcp-client
add interface=VLAN2-WAN script=":if (\$bound=1) do={\r\
    \n  :log info \"DHCP client interface: \$\"interface\"\"; \r\
    \n}"
2
3

Thanks, Conrad. I’ve edited the original post.

4

I found what I’m looking for in the ARP List: “Bridge Port”. Unfortunately, that is not a value you can retrieve in a script.

5

ARP and DHCP are usually completely independent, you can disable ARP learning and have the DHCP server create an ARP entry for specific use cases.

Enabling DHCP snooping on the bridge will populate the agent-circuit-id and agent-remote-id fields which may provide the information you are looking for.

I’m not sure of what use this information will be - there is little configuration you can apply to an interface which is a bridge port, most configuration should be applied to the parent bridge.