rarpd —
Reverse ARP Daemon
  
    | rarpd | [ -adfl] [interface
      [...]] | 
rarpd services Reverse ARP requests on the Ethernet
  connected to interface. Upon receiving a request,
  rarpd maps the target hardware address to an IP
  address via its name, which must be present in both the
  ethers(5) and
  hosts(5) databases. If a host
  does not exist in both databases the translation cannot proceed and a reply
  will not be sent.
In normal operation, rarpd forks a copy of
    itself and runs in the background. Anomalies and errors are reported via
    syslog(3).
  - -a
- Listen on all the Ethernets attached to the system. If
      ‘-a’ is omitted, an interface must
      be specified.
- -d
- Run in debug mode, with all the output to stderr. This option implies the
      -foption.
- -f
- Run in the foreground.
- -l
- Log all requests to syslog.
bpf(4),
  ethers(5),
  hosts(5)Finlayson, R.,
    Mann, T., Mogul, J.C., and
    Theimer, M., A Reverse Address
    Resolution Protocol, RFC 903.