Third Party may enforce his rights to the contract if:
1) The third party has communicated his assent by word or by conduct (he has already started to carry out his contractual obligations).
2) Promisor has already known about reliance.
3) Promisor can reasonably ascertain third party has relied on the contract.
This is also subjected to exceptions:
1) Third party's whereabouts are unknown.
2) Third Party is mentally incapable.
3) Promisor cannot reasonably ascertain whether he has relied on the contract or not.
Promisor on the other hand may subject himself to certain defense:
1) Terms of contract provides that he can.
2) Liability arises from contract and relevant to the terms of contract.
3) Terms that promisor use against or for promisee, he can use against or for on third party.
4) Prevent double liability from third party as well as promisee. If promisee have claimed damages from third party, the court may prevent promisee from claiming damages from promisor or reduce the amount of damages claimable.
Hope this is useful to you!
what we could have been, 10:44 PM.