The striker, 27, who was manager Nigel Clough's first signing for the club in January 2009 from SPL side side Motherwell, has endured an injury-plagued spell at Pride Park.
Porter made 25 starts and 25 substitute appearances during his two-and-a-half years with the club, scoring nine goals.
Winger Greg Mills, who has spent the majority of this season on loan at Telford, and midfielder Arnaud Mendy are the other players that have been told their contracts will not be renewed this summer.
Meanwhile, goalkeepers Saul Deeney and Ross Atkins will be offered new deals while the option has also been taken up on James Severn's contract to remain with the Rams for a further year.
Academy products Callum Ball, Alex Witham, Aaron Cole and Chris Jones will become first-year professionals next season...
Source: PA
Source: PA