# allow main google
User-agent: Googlebot
Disallow:
Crawl-delay: 20
Request-rate: 1/20        # maximum rate is one page every 20 seconds
Visit-time: 0400-1100     # only visit between 4:00 AM and 11:00 AM UT (GMT) (11PM-6AM EST)

# allow MIT Google
User-agent: gsa-crawler
Disallow:
Crawl-delay: 20
Request-rate: 1/20        # maximum rate is one page every 20 seconds
Visit-time: 0400-1100     # only visit between 4:00 AM and 11:00 AM UT (GMT) (11PM-6AM EST)

# allow Yahoo
User-agent: Slurp
Disallow:
Crawl-delay: 20
Request-rate: 1/20        # maximum rate is one page every 20 seconds
Visit-time: 0400-1100     # only visit between 4:00 AM and 11:00 AM UT (GMT) (11PM-6AM EST)

# allow MSN
User-agent: MSNBot
Disallow:
Crawl-delay: 20
Request-rate: 1/20        # maximum rate is one page every 20 seconds
Visit-time: 0400-1100     # only visit between 4:00 AM and 11:00 AM UT (GMT) (11PM-6AM EST)

# everyone else
User-agent: *
Disallow: / 
Crawl-delay: 20
Request-rate: 1/20        # maximum rate is one page every 20 seconds
Visit-time: 0400-1100     # only visit between 4:00 AM and 11:00 AM UT (GMT) (11PM-6AM EST)