It seems that the SIP ALG feature is never useful, and in fact always causes problem. Then why do ALL the router vendors in the world routinely, mindlessly, stubbornly and tirelessly add this (mis-)feature to ALL of their router products, day after day, year after year?
Who in the world really benefits from using this SIP ALG feature in a router?
Are these engineers from the router vendors never reading Internet forum posts? Aren't they aware of all the complaints on SIP ALG feature all over the world?
Or is there any hidden agenda behind this act that cannot be disclosed to the general public?