  Galaxies are usually classified as star forming or active by using diagnostic
diagrams, such as [N II]/Halpha vs. [O III]/Hbeta. Active galaxies are further
classified into Seyfert or LINER-like sources. We claim that a non-negligible
fraction of galaxies classified as LINERs in the Sloan Digital Sky Survey are
in fact ionized by hot post-AGB stars and white dwarfs.
