It is generally recommended that hot dogs be frozen for no more than 2 months - but that has to do with deterioration of quality, rather than health safety. Personally, I think the trash can would be a pretty good place for two year old hot sausage - but that's me.
I got to thinking about it, and decided to look further than my memory for info. I found this:
Food Safety Guidelines
The same general food safety guidelines apply to hot dogs as to all perishable products ? "Keep hot food hot and cold food cold."
When you leave the grocery store with hot dogs, head straight home and refrigerate or freeze them immediately. If there is no product date, hot dogs can be safely stored in the unopened package for 2 weeks in the refrigerator; once opened, only 1 week. For maximum quality, freeze hot dogs no longer than 1 or 2 months. And, of course, never leave hot dogs at room temperature for more than 2 hours and no more than 1 hour when the temperature goes above 90 ?F.
Although hot dogs are fully cooked, those at increased risk of foodborne illness should reheat hot dogs and luncheon meat until steaming hot before eating, due to the threat of listeriosis. Hot Dogs and Food Safety