8.????????????????IP??DNS??????NCSA?е?access.conf?м????

??Directory??/full/path/to/directory??

??Limit??GET??POST??

order??mutual-failure

deny??from??all

allow??from??168.160.142.??abc.net.cn

??/Limit??

??/Directory??

????????????????abc.net.cn??IP????168.160.142?????????Web????????

????CERN??W3C????????????????httpd.conf?м????

Protection??LOCAL-USERS??{

GetMask??@(*.capricorn.com????*.zoo.org????18.157.0.5)

}

Protect??/relative/path/to/directory/*??LOCAL-USERS

9.WINDOWS??HTTPD

(1)Netscape??Communications??Server??for??NT

PERL?????????????

Netscape??Communications??Server????????CGI-BIN?μ????????????ù??????.pl?????PERL????????????????????????????????????perl.exe????????CGI-BIN??????????磺/cgi-bin/perl.exe?&my_script.pl??????????κ?????????PERL??????????Щ?????????????URL?м????磺/cgi-bin/perl.exe?&-e+unlink+%3C*%3E????п???????????????????????????Σ?????????????磺O??Reilly??WebSite??Purveyor?????????????????

CGI?????????????????:

???test.bat?????????￡?

@echo??off
echo??Content-type:??text/plain
echo
echo??Hello??World!

?????????????URL???/cgi-bin/test.bat?&dir??????е???????????????DIR?б?????÷????????????????????????

(2)O??Reilly??WebSite??server??for??Windows??NT/95
??WebSite1.1B?????汾??????????????????????Netscape????????????????°?????.bat??CGI?е????á????PERL???°潫VB??C???CGI?????????

(3)Microsoft??s??IIS??Web??Server

1996??3??5?????IIS??NT?μ?BUG????????????????command??????????????????????????????????????????????IIS3.0???????Щ???BUG???????CGI-BIN?μ????????????????Web????????????????Щ?????????????????汾?????????б??????????????????о????

??.????CGI??????????

1.????????????????????????Щ??????CGI??????????????HTML?????????CGI-BIN?￡???????????Щ???????????????????y???????????????????????????

2.????C????дCGI??????????????popen()??system()???????漰/bin/sh??SHELL?????????PERL?е?system()??exec()??open()??eval()??exec??eval??????

?????????д??form????CGI????????????system()???????

????????????????????????SSL??SHTTP??SHEN??Э?鷯????о???

??.???????(Firewall)

1.??????????

?????(Firewall)????????????????????????豸???????????????????????????????????(Internet)?????????????????????????????????????????????????????

2.?????????

(1)????(Proxy)????"???????--????????(Proxy??Gateway)--Internet"

?????????????????Internet??????????????????????????????????????????????????????????Э??(Netbios??TCP/IP??)??????????Internet???????????TCP/IP??????Э?顣??????????????????????????????????????С???????????????????????????Internet????????????????????????????????????????????????????????????????????????????ò??Э????????????????????????????У?????????????????????????????????????????????????????????????????????????????????????????á?

??????????????????????????????????У???????????????Ч??????????????????????????????????????Internet?????????????????????п??????????????Internet??

(2)·??????????????

"???????--??????(Filter)--·????(Router)--Internet"

???????·??????????????????IP????????????????????????????????????????????????????????????Internet??·???????????????????PORT?????????????·?????????????????????????????????????????????????????????????????????????????