Ipswich Town’s wait for an FA Cup win goes on, although Andre Dozzell did spare the Blues blushes and kept his side in the competition.
The draw extends the Blues' winless run in the competition to 15 games, but it could have been far worse had Tyler Walker been able to add to his first-half goal from the penalty spot after the break, following a clumsy Toto Nsiala tackle.
Will Norris got him out of jail as he made a solid stop and within minutes Ipswich were level when Dozzell curled the ball into the net as the hosts pressed for a route back into the game.
It wasn't always pretty, but Paul Lambert's men were able to raise their game after the interval and ultimately deserved to take this tie to a replay.
That game will be played in Wednesday November 20.
Lambert made 10 changes to his side, switching his entire outfield following the 1-0 win at Rochdale in midweek.
That meant chances for Janoi Donacien, Toto Nsiala, Andre Dozzell and Anthony Georgiou to stake a claim, while Will Keane and captain-for-the-day Emyr Huws got more minutes in their legs.
The only man to keep his place was goalkeeper Will Norris and, after cleverly turning around advancing striker Tyler Walker with his first real touch of the ball, made a good low save to stop Jack Payne a few minutes later.
James Wilson survived some desperate Lincoln penalty appeals after Jake Hesketh went down easily inside the box, before Keane had Town's first effort of the afternoon as he shot straight at Josh Vickers after being threaded through following excellent work by Flynn Downes.
Walker, son of former England defender Des, glanced a header over the bar as Lincoln sounded the warning siren, before Hesketh blazed over the top of the bar.
That was the final let-off for the Blues, as Walker slammed home from Bruno Andrade's cross to spark thoughts of the inevitable once again as the striker celebrated with cupped ears in front of the North Stand. The striker looked to be offside, but there was nothing doing as the Blues trailed at the break.
Despite some nervy moments at the back, the hosts stepped things up after the interval and began to push higher up the field, with Downes first having a shot down the throat of Vickers from outside the box before Keane couldn't quite direct a head from Georgiou's cross on target.
They continued to push, with Dobra dancing into the area and causing chaos which ultimately led to Keane's shot being blocked, before Lincoln broke at speed only for Norris to produce an excellent save to keep Walker out.
Nsiala produced an excellent header to dig a dangerous Bruno Andrade cross out of danger, before two driven Ipswich crosses, first from substitute Gwion Edwards and then Huws, just evaded Keane.
The air inside Portman Road was filled with dread when Nsiala's clumsy challenge on Hesketh gave away the penalty which threatened to end the game as a contest. Thankfully the defender's blushes were spared as Norris made the save from Walker's poor penalty, with the striker then poking the rebound wide when he really should have scored.
That lifted the crowd which then lifted the team, with the equaliser coming soon after as Dozzell's curled effort into the box crept into the net at the far post.
The Blues pushed for a winner, introducing James Norwood, but it never came and the two teams will do it all again at Sincil Bank.
Ipswich Town: Norris, Donacien, Nsiala, Wilson, Kenlock; Huws, Downes (Rowe, 84); Dozzell, Dobra (Edwards 65), Georgiou (Norwood, 85); Keane
Subs: Holy, Woolfenden, Judge, El Mizouni
Lincoln City: Vickers; Eardley, Shackell, Connolly, Toffolo; O'Connor (Chapman 50), Morrell; Andrade (Anderson, 83), Payne, Hesketh (Grant 77) ; Walker
Subs: Smith, Lewis, Melbourne, Akinde
Att: 11,598 (1,190 away fans)
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