Speaking to the Ipswich Evening Star, John said: "The chance to come to Ipswich was out of the blue but it didn't take me long to decide to come here.
"I have to take one step at a time and see what happens in January, but for sure I'd like to stay longer.
"My contract at Crystal Palace ends next summer, though with a possible one-year extension depending on appearances. But I'm a million miles away from that."