Requests to http://search.musicbrainz.org/ currently go directly to the Lucene servers without any rate-limiting. These servers are a contended resource and so all access to them needs to be rate-limited.

Possible implementation:

• nginx proxies requests to some mod_perl-enabled apache server
• that mod_perl server applies the rate limiting, perhaps in a PerlFixupHandler
• if not blocked by rate limiting, apache rewrites the request to a proxy back to the private search nginx load balancer