TESTRBL <ip>

Spot-checks a single IPv4 or IPv6 address against every
configured blocklist{} (DNSBL/RBL) zone, without affecting
any client. Useful for verifying that a zone is reachable,
that a known-bad address is being flagged, or that a
false-positive complaint is reproducible.

For each configured zone the server dispatches an
asynchronous DNS query and emits one notice. The notice
text is prefixed "TESTRBL <ip>: <zone> - " followed by:

  MATCH reply=<addr> - <reason>
                Zone returned a record matching one of the
                configured answer masks; the substituted
                ban reason is shown.
  reply=<addr> (no configured match rule hit)
                Zone returned an answer but it did not
                match any configured answer{} mask and the
                zone is not configured matchother.
  CLEAN (no listing)
                The zone did not return a positive
                listing. In the typical case this is
                NXDOMAIN; the resolver also reports it
                this way for some other non-success
                conditions (e.g. forward/reverse address
                mismatch, oversized hostname). Treat as
                "not banned by this zone" but do not
                read it as an authoritative negative.
  ERROR (resolver helper unavailable)
                The resolver helper rejected the lookup
                (typically because the helper is down).
  unexpected address family in reply
                Zone returned a non-IPv4 record (protocol
                oddity, not a normal RBL response).
  malformed response (<text>)
                Zone returned a response that did not
                parse as an IPv4 address.
  TIMEOUT after <N>s
                No answer within the per-session timeout.

A terminating notice is sent once every zone has answered
or timed out:

  End of /TESTRBL
  End of /TESTRBL (with timeouts)   (one or more timed out)

Reuses the normal RBL lookup path but does not modify the
issuing oper's connection state and does not ban anyone.

See also: STATS n (per-zone query/match/miss counters).
