By using the combined power of 13 instances of the TARDIS, in "The Day of the Doctor", they "froze" Gallifrey "You know, like those stasis cubes? A single moment in time, held in a parallel pocket universe."
As the War Doctor & the Tenth Doctor explained to Clara:
- WAR DOCTOR: The Dalek fleets are surrounding Gallifrey, firing on it constantly.
- TENTH DOCTOR: The Sky Trench is holding, but what if the whole planet just disappeared? [...] The Daleks would be firing on each other. They'd destroy themselves in their own crossfire.
- WAR DOCTOR: Gallifrey would be gone, the Daleks would be destroyed, and it would look to the rest of the universe as if they'd annihilated each other.
- CLARA: But where would Gallifrey be?
- TENTH DOCTOR: Frozen. Frozen in an instant of time, safe and hidden away.
Thus, the planet was removed from the main universe (& therefore from the war). In the process, the Daleks were almost completely destroyed -- by their own weaponry -- when their target suddenly vanished.
As the Twelfth Doctor (the latest incarnation involved in saving the planet) discovered at the end of "Heaven Sent", Gallifrey eventually returned to the main universe. As far as we know (as of the end of Series 10), the Daleks have not yet discovered this.