Dons skipper Dean Lewington broke the deadlock with a 55th-minute header and Easter added a double before substitute Josh Scott pulled a goal back for the Daggers at the death.
Dagenham striker Paul Benson twice went close to opening the scoring in the first half, first when he was denied one-on-one by Willy Gueret and then when he charged down a kick from the Dons goalkeeper and the ball rebounded inches wide.
But Lewington scored his first goal of the season to put the Dons ahead 10 minutes after the break, heading in Richie Partridge’s in-swinging cross from 10 yards following goalkeeper Tony Roberts’ weak punch.
Easter doubled the lead two minutes later with a neat swivel and finish from four yards after Roberts had tipped Mathias Doumbe’s header onto the woodwork.
Dons top scorer Easter made it 3-0 in the 67th minute when his fierce 25-yard drive squirmed past Roberts before Scott nodded in Mark Arber’s knock-back from Graeme Montgomery’s corner for the Daggers three minutes into stoppage time.