防火墻安全技術(shù)分析比較
9700多字 10頁(yè)


摘要
防火墻（Firewall）是用一個(gè)或一組網(wǎng)絡(luò)設(shè)備（計(jì)算機(jī)系統(tǒng)或路由器等），在一個(gè)或多個(gè)網(wǎng)絡(luò)間加強(qiáng)訪問(wèn)控制，以保護(hù)一個(gè)網(wǎng)絡(luò)不受來(lái)自另一個(gè)網(wǎng)絡(luò)攻擊的安全技術(shù)。防火墻的組成可以表示為：防火墻=過(guò)濾器+安全策略（+網(wǎng)關(guān)），它是一種非常有效的網(wǎng)絡(luò)安全技術(shù),是隔離在本地網(wǎng)絡(luò)與外界網(wǎng)絡(luò)之間的一道防御系統(tǒng)，是這一類防范措施的總稱。本文主要是針對(duì)現(xiàn)有防火墻的類型中的包過(guò)濾和代理防火墻兩種作出分析及比較。通過(guò)兩種類型的工作方式，流程來(lái)比較了他們的優(yōu)缺點(diǎn)，以此了解到他們各自的適用性。

關(guān)鍵字
防火墻，包過(guò)濾、應(yīng)用代理服務(wù)器、代理,網(wǎng)關(guān),IP地址

Analyzing and Comparing Of Firewall’s
Safety &Technology



Abstract: Firewall is a technology which is made up of one or a group of network equipment (Computer language or Router…).The firewall can command one or more network could not be attacked form another. The compose of firewall can be amounted: Firewall=Filter + Safety policy (+Application Gateway). It is a very availability technology. Firewall can segregate local network from the outside, all these range can call Firewall. The text of this passage compare two types of Firewall (Packet filter & Application-level Proxy Server) and analyses which both of two excellences and disadvantages from their working elements, we can know about the types of two firewall would do well in different jobs.

Key words: Firewall, Packet Filter, Application-level Proxy Server, Proxy,
Application Gateway, IP address

1 引言
1.1 從包過(guò)濾到應(yīng)用代理
防火墻技術(shù)本身經(jīng)歷了3次巨變。早期的防火墻只是采用簡(jiǎn)單的“包過(guò)濾”技術(shù)——即對(duì)進(jìn)出網(wǎng)絡(luò)的數(shù)據(jù)包進(jìn)行檢查，雖然效率高，但漏洞大，缺乏安全性，很快被淘汰出局。隨后的應(yīng)用代理技術(shù)讓通信經(jīng)應(yīng)用代理層轉(zhuǎn)發(fā)，可徹底隔斷兩端的直接通信，可想而知，安全性增加很多，卻以犧牲效率為代價(jià)......