This was Ipswich's 14th game without defeat at home - 13 of them victories - but at the same time they have failed to win away from home in nine months and 15 games.
Pablo Counago's early strike gave them the ideal lift after back-to-back away defeats last week, but this was cancelled out by Iain Hume's clever lob, before a controversial penalty turned the game.
Patrick Kisnorbo was penalised for a foul on Counago and harshly sent off as the last man before Alan Lee tucked home the penalty.
Jon Walters wrapped up the points with a third after the break, but Ian Holloway's men did well to keep the scoreline respectable.
Marton Fulop saved early on from Walters but it was a very quiet opening before Danny Haynes sprinted to the byline beyond Joe Mattock and crossed for Counago to control and fire into the roof of the net on 19 minutes.
Town appealed for a penalty when Walters appeared to be pulled back at a corner, but on 27 minutes Leicester were level when Hume controlled a header forward to coolly lob Neil Alexander from 15 yards.
Counago headed narrowly wide from a David Wright cross and the Spaniard could have had a second only for strike partner Lee to cross just behind him, before Walters fired over from the loose ball.
The game turned on 39 minutes when the linesman indicated Kisnorbo's challenge on Counago was a foul, but due to the angle it was a surprise when ref Phil Joslin produced a red card, prompting furious Foxes protests.
Lee coolly tucked home the spot kick, sending Fulop the wrong way, having missed a penalty in Saturday's 3-1 defeat at fellow play-off hopefuls Charlton.
Haynes was then denied by Fulop after being slipped in by a lovely ball from Owen Garvan as Ipswich ended the half on top.
The second half began evenly, despite Ipswich's numerical advantage, and, after Garvan had a fierce shot blocked, Hume's goalbound effort was charged down at the other end by fellow Canadian Jason De Vos.
Ipswich built up a good spell of pressure with Walters, Garvan and Counago all going close before they sealed the points when Counago flicked on a Gavin Williams cross and Walters volleyed in at the far post.