Retrieve the public IP address of a specific Mikrotik RouterBoard interface.

script.txt

:global getPublicIP do={

  # tag for temporary configurations
  :local tag "get-public-ip-via-$interface"

  # service that provides public ip address in http response
  :local lookupProtocol "https"
  :local lookupHostname "api.ipify.org"

  # add temporary address list for lookup service
  /ip firewall address-list add list=$tag address=$lookupHostname comment=$tag timeout=15s
  :delay 3;

  # configure temporary route to lookup service via a specific interface
  :foreach p in=[/ip firewall address-list find comment=$lookupHostname dynamic=yes] do={
    :local addr [/ip firewall address-list get $p address];
    /ip route add gateway=$gateway dst-address=$addr comment=$tag
  }

  # fetch http response from lookup service
  :local result [/tool fetch url="$lookupProtocol://$lookupHostname" as-value output=user]

  # remove temporary address list
  /ip firewall address-list remove [find where comment=$tag]

  # remove temporary gateway route
  /ip route remove [find where comment=$tag]

  # return ip from lookup service response data
  :return ($result->"data")

}

# get public ip addresses
:local iplte [$getPublicIP interface="lte1" gateway="192.168.8.1"]
:local ipfibre [$getPublicIP interface="Fibre-PPPoE" gateway="Fibre-PPPoE"]

# log ips
:log info "Fibre IP: $ipfibre"
:log info "LTE IP: $iplte"