McAuley benefited from poor Ipswich marking, and the hosts must also be concerned about relegation after failing to score for a third successive game.
The victory completed a double for Leicester - after their 3-1 win at the Walkers Stadium in August - a performance Town boss Jim Magilton labelled the worst under his management.
This wasn't much better and Ipswich's misery was compounded when talented midfielder Owen Garvan foolishly got himself sent off for a two-footed lunge, having already been booked.
Leicester began in confident fashion and loanee striker Geoff Horsfield headed Alan Maybury's cross over inside the first minute.
Ipswich then got a grip on proceedings with Billy Clarke firing a volley wide before Jon Walters had a shot on the turn blocked from a Dan Harding cross.
Maybury nipped in ahead of Clarke to clear a dangerous Jaime Peters flick-on before Walters had the ball in the net, neatly turning and firing in off the post from a Garvan long pass, only to be adjudged offside.
The best chance of the early stages fell to Ipswich on 19 minutes when Sylvain Legwinski flicked on a Harding cross and Peters met it with a firm angled low volley which Paul Henderson did well to parry.
A minute later, an unmarked Horsfield wasted Leicester's best early chance when he headed Mark Yeates' cross straight at Lewis Price.
Price denied Iain Hume from 20 yards before Leicester went ahead on 28 minutes. Levi Porter swung in their first corner and McAuley shrugged off Legwinski before heading in from six yards.
Town almost equalised a minute later but Darren Currie's pinpoint free-kick, which was set to be headed home by Peters, was taken off him by Clarke who, stretching, could only head over.
It could have been 2-0 on 31 minutes when Fabian Wilnis failed to control a loose ball in his own box and Hume lashed goalwards from a tight angle, forcing a good block from Price.
Peters shot wide from an angle and Henderson saved a Clarke flick from David Wright's cross before Leicester, in first-half stoppage time, mounted a swift break which ended with Wright charging down Porter's drive.
Garvan earned his first yellow card three minutes after the break for tripping Andy Johnson, even though the ex-Norwich man tried to talk referee Carl Boyeson out of it.
Ipswich mounted a swift break on 50 minutes which saw Walters play Clarke in behind the defence and, from a tight angle, he did well to get a shot in on goal which Henderson tipped over.
Clarke shot wide before Leicester doubled their lead on 56 minutes with their first real attack of the second half.
Porter took a short corner to Yeates, who whipped in a cross which Price came for but was easily beaten to by McAuley, who nodded into an empty net.
Peters shot wide as Ipswich tried to rally and both Horsfield and Porter failed to hit the target from decent positions at the other end for the Foxes.
Horsfield had a chance with an overhead kick when Jason Jarrett nodded down Porter's cross but the veteran striker failed to make any connection.
Walters sent an angled shot not far wide before Town made a double change midway through the half, bringing on Danny Haynes and George O'Callaghan for Clarke and Legwinski respectively.
Almost immediately, Garvan foolishly ended any chance of a rally when he launched himself two-footed as he and Porter closed in on a loose ball, and the referee showed him a second yellow card - it could easily have been a straight red.
Despite the one-man disadvantage, Ipswich came close on 73 minutes when Walters headed goalwards from a Wright cross and, although it left Henderson helpless, skipper Patrick Kisnorbo was in the right place to clear acrobatically.
Ipswich had another good chance on 81 minutes when Peters swung in a dangerous cross. Haynes got a glancing header in which was just too firm for Walters to make contact with in front of an empty net.
Peters also shot narrowly wide from 20 yards as the game entered stoppage time but in truth Leicester played out time comfortably and sealed a surprisingly easy double success over the Suffolk side.
On this evidence, Rob Kelly's side should have little trouble in collecting sufficient points to ensure they stay in the Championship, but Ipswich still have work to do, although they will point to a number of key players being out at present.