His side took the initiative early on with Andre Boucaud's seventh minute shot flying past the outside of Mark Goodlad's left-hand post from 25 yards.
Only two minutes later, the Valiants were penned back again when Calum Willock forced a fingertip save from the goalkeeper.
Vale's first shot arrived on 32 minutes when Tony Dinning burst across the edge of the area and produced an effort that dipped just over.
Mark Tyler was called into action seconds before the break when Lee Matthews turned Sean St. Ledger to shoot, but the goalkeeper saved smartly.
The home team started the second half well with Christopher Birchall shooting over from close range almost straight from the kick-off.
Posh struggled to get forward and almost got lucky after 54 minutes when Ahmed Deen's cross had to be pushed over the bar due to the high winds.
An opening did arrive in the form of on-loan Dinning when he headed home a right-sided Birchall cross at the back post on 63 minutes to break the deadlock.
An equaliser never seemed possible for Fry's men even with the fresh legs of Adam Newton and Wayne Purser midway through the half.
Andy Clarke's late free-kick offered the only hope of levelling the scores but it proved no danger to Port Vale's lead.