Terry Baxter, Towns Director of Communications told the club site: "Ipswich Town have asked Northampton for permission to speak to Colin Calderwood about the vacant manager's position at Portman Road and that permission has been granted.
"Colin is one of a number of candidates being interviewed for the position."
Calderwood has been in charge of the Cobblers for three years and led them to promotion to League one in the 2005-06 season. The former Scotland international is contracted to Northampton until 2008 and Town would have to pay compensation should Calderwood take the job.