Defeat would have been cruel on the hosts who dominated possession and posed the greater overall threat, but were generally wasteful in the final third.
A point apiece means the gap to second-placed Middlesbrough remains at two points following Boro’s draw away at Blackburn Rovers.
The real winners were Coventry City, who could go nine points clear at the top of the table with victory over Swansea City in the evening kick-off.
Town looked in good shape to be the team leading the charge in the first period, with Dan Neil sending a shot narrowly wide, Darnell Furlong having a header cleared off the line by Jake Cooper and only a staggering one-handed reaction save from Lions keeper Anthony Patterson keeping the score at 1-0.
Millwall only threatened occasionally, notably when Neghli’s strike forced a fine stop from Town keeper Christian Walton.
But they played with far greater tempo after the interval and were soon level thanks to Coburn’s cleverly constructed goal and came so close to snatching victory late on, only for Walton to superbly deny Femi Azeez before Ivanovic’s follow-up strike bounced to safety.
The Lions will next travel to Middlesbrough on Friday 3 April, while Ipswich will not be in action again until the following Monday, when they host Birmingham City at Portman Road.