Cops tell us the jumper was a 17-year-old from Maryland.

Practice makes perfect -- Secret Service agents nailed a White House jumper Wednesday, and this time it went like clockwork.

The Secret Service says the jumper attempted to scale the now infamous bike rack fence around 4:30 PM ET, but agents took down the individual before they made it over. The suspect's been booked for unlawful entry.

This makes SIX attempts to get on White House grounds ... with one suspect making it all the way to a door before agents apprehended him.

The Secret Service has not released any information about the latest jumper.