middlebox

基本解释

The anonymity and inaccessibility of the internal hosts behind a middlebox is not a problem for client software such as web browsers, which only need to initiate outgoing connections.
這樣的話，這些匿名的竝且看起來難以觸及的藏在NAT之後的內網主機對於像Web瀏覽器這種軟件來說就不是一個問題,因爲內網的主機衹需要發起曏外部的連接就可以了。
In this section we first summarize some middlebox terms. We focus hereon the two kinds of middleboxes that commonly cause problems for P2P applications.
在這一章節中，首先概要的介紹一下““代理””技術的一些術語。然後集中討論兩種造成P2P應用問題的代理機制。