Middleboxes No Longer Considered Harmful
Intermediate network elements, such as Network Address Translators (NATs), firewalls, and transparent caches are now commonplace. The usual reaction in the network architecture community to these so-called middleboxes is a combination of scorn (because they violate important architectural principles) and dismay (because these violations make the Internet less flexible). While the authors acknowledge these concerns, they also recognize that middleboxes have become an Internet fact of life for important reasons. To retain their functions while eliminating their dangerous side-effects, they propose an extension to the internet architecture, called the Delegation-Oriented Architecture (DOA), that not only allows, but also facilitates, the deployment of middleboxes.