How did Homer depict war as not heroic in the Iliad?

On the surface, the Iliad is a story glorifying war and martial prowess. Careful reading, however, reveals that Homer does not see war as a means to glory and happiness, but insetead sees it as the primary reason for man's insecurity, unhappiness, and despair. How did Homer depict an ideal of peace rather than war? What are examples from the Iliad of Homer not portraying war as heroic?