Andy Carroll had headed United in front and Shola Ameobi hit the other from the spot with Connor Wickham replying in between.
It means United must gain at least a point in the season ender at QPR to top the 100 points mark.
Newcastle did though equal a 103-year record when they went throughout the season unbeaten at home.
In front of a record Championship attendance of 52,181 it was Newcastle who opened the scoring after 27 minutes with Andy Carroll's 19th goal of the campaign.
Wayne Routledge was once again the supplier from the left, his cross into the six-yard box was powerfully headed in by the Gateshead-born marksman who moved clear in the United scoring stakes.
But just a couple of minutes before the break it was Ipswich who equalised through the highly-rated Connor Wickham as he hit his second in successive matches.
It was a stunning piece of work from the 17-year-old Sunderland target who showed great control when gathering a long ball to beat Steve Harper from12-yards.
Former Sunderland player Grant Leadbitter came close to giving the Tractor Boys an interval leads when his 20-yard effort flew narrowly wide.
After starting the opening half the better side, it was same again by Ipswich as they forced Newcastle on the back foot.
The Geordies hit back and Peter Lovenkrands put a good chance high and wide before a timely intervention by Tommy Smith curtailed a Kevin Nolan chance.
Butt, taking part in his last game before retiring at the end of the season, was to play a major role as United regained the lead.
He was floored after 84 minutes by Leadbitter and substitute Shola Ameobi rammed United in front from the penalty spot.
But the euphoria sweeping the ground was temporarily quietened in the fourth and final minute of added time when Jon Walters equalised.