first of all the title is wrong why only ally or foe? Iran and Pak can be neutral friends.
secondly I surprised some one looking in relation of both but only from one side interests.
if you think Iran -India relations is aganst Pak interests how about US-Pak relations US threat to Iran is more than indian to Pak.same about Pak-Saudi relations.
Pak was at least the host for a anti-Iran terrorist group( Jondullah) if we do not say supporter while Iran have done many good to Pak (Iran offered cheaper electricity to pak but pak is not ready, Iran is ready to supply cheaper gas to Pak but Pak play with US by this card to gain more benefit, Iran had Pak aid day for Pak flood and Pak received the most aid from Iran while your media casted that US and Saudi were bigger helper,......) I can make a bigger list, maybe Pak can make a list against Iran too. what I am trying to say is relations seeks for bilateral interests, you can not ask one side offer %100 to you or leave all benefits for you, as Pak has interest in Afghanistan Iran has interest there too, then why should Iran left everything for Pak there, the point is two sides must work to achieve to common interest rather than blaming each other