Jason Scotland's long-range strike earned Ipswich a point as Palace drew their 11th home game of the season.
Ipswich were arguably the better side in the first half and they gave Eagles goalkeeper Julian Speroni plenty to do.
But Palace went ahead after Nathaniel Clyne linked well with Sean Scannell before delivering a cross for Chris Martin, who fired in from 12 yards.
The equaliser came just before the hour when Grant Leadbitter fed Scotland, whose shot skidded past Speroni.
As well as succumbing to another home draw Palace are now on a six-match winless run and it might have been worse had it not been for their goalkeeper Speroni.
After just three minutes Lee Martin's long-range drive was gathered uneasily by Speroni, who scampered across his goal moments later as Andy Drury's ambitious shot flew narrowly wide.
Leadbitter then arrowed a shot wide from 25 yards before Jay Emmanuel-Thomas stung Speroni's palms with a strike from even further out.
Speroni's one-man resistance continued in the 25th minute as Scotland's well-timed volley was parried to safety and then Emmanuel-Thomas was denied from distance.
Against the run of play, Chris Martin, who is on loan at Palace from Norwich, capitalised on the good work of Clyne and Scannell to put the home side into the lead.
After an even start to the second half it was Ipswich who made the first decisive move.
Leadbitter fed Scotland and he weighed up his options before unleashing a shot from outside the area that was too good for Speroni.
Aaron Cresswell saw a late shot blocked, while substitute Kyle De Silva went close for Palace.