For 16 minutes there was hope as Rotherham United put a dire first-half display behind them to hint at a remarkable comeback
Trailing 4-0, the Millers fought back to 4-2 before the hour mark, but Daryl Murphy's hat-trick goal for Ipswich Town in the 72nd minute ended the contest.
Debutant Brandon Barker scored with a beautiful bending shot in the 56th minute and Matt Derbyshire fired in a stunning volley three minutes later as the home side tried to turn the game around.
They were two moments of Millers quality far removed from the opening 45 minutes as Town swept into a 3-0 through Brett Pitman, Jonathan Douglas and Murphy, with Murphy adding his second just after the break.
Rotherham turned in an inept first-half performance. Midfielder Paul Green bore the brunt of the abuse from fans as he was at fault for the opening two goals but there were poor individual displays everywhere.
After the break, they were a different side, and had strong appeals for a penalty turned down as substitute Jonson Clarke-Harris looked to be pushed over in the area by Christophe Berra when the score was 4-2 and all the momentum was with Rotherham.
Redfearn handed debut to 19-year-old Barker, brought in on loan from Manchester City, and preferred Derbyshire, fit again after a knee problem, to Clarke-Harris up front.
Defeat leaves the home side rooted at the foot of the Championship table and Redfearn still searching for his first win after six games in charge
Rotherham United (4-4-2): Camp; Richardson, Rawson, Collins, Toffolo (Buxton 85); G Ward, Thorpe (Smallwood H-T), Green (Clarke-Harris H-T), Barker; Derbyshire, D Ward. Subs not used: Collin, Broadfoot, Newell, Andreu.
Ipswich Town (4-4-1-1): Gerken; Chambers, Smith, Berra, Knudsen; Bru (Maitland-Niles 66), Skuse, Douglas, Sears (Coke 81); Pitman; Murphy (Parr 90). Subs not used: Bialkowski, Oar, Malarczyk, Toure.
Goals: Barker 56, Derbyshire 59 (Rotherham); Pitman 8, Douglas 22, Murphy 42, 48, 72 (Ipswich).
Referee: Darren Drysdale (Lincolnshire).
Attendance: 9,162 (1,019).