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Jul 19th, 2008, 5:49am
   Mischel Internet Security Forum
   Internet Security
   Firewalls (Moderators: Helena, Gavin_Coe, Magnus)
   proxy firewall and this scenario from Forouzan Boo		 « Previous topic | Next topic »
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   Author  Topic: proxy firewall and this scenario from Forouzan Boo  (Read 1026 times)
zillah
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proxy firewall and this scenario from Forouzan Boo
« on: Jun 8th, 2006, 5:41am »		 Quote Quote  Modify Modify
I have got this scenario from Forouzan Book "Data Communications and Networking" 3ed  
 
Code:
http://highered.mcgraw-hill.com/sites/0072515848/student_view0/chapter31 /powerpoint_slides.html

 
He says in page 851 :
 
"When the user client process sends a message, the proxy firewall runs a server process to receive the request. The server (I said it is the HTTP proxy )opens the packet at the application level and finds out if the request is ligitimate. If it is, the server acts as a client process and sends the message to the real server (I said it is the HTTP Sever) in the corporation. If it is not, the message is dropped and an error message is sent to the external user. Figure 31.11 shows a proxy firewall implementation".
 
Code:
http://img234.imageshack.us/img234/1307/proxyfirewallforouzanch310bc.jpg

 

 
 
If the proxy firewall can investigate (check ) the application layer by itself , why do I need to send the packet to the HTTP proxy ?
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zillah
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Re: proxy firewall and this scenario from Forouzan
« Reply #1 on: Jun 13th, 2006, 12:08am »		 Quote Quote  Modify Modify
Any idea ?
« Last Edit: Jun 13th, 2006, 12:10am by zillah » IP Logged
devnull
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Re: proxy firewall and this scenario from Forouzan
« Reply #2 on: Jun 21st, 2006, 3:24am »		 Quote Quote  Modify Modify
on Jun 8th, 2006, 5:41am, zillah wrote:
I have got this scenario from Forouzan Book "Data Communications and Networking" 3ed  
 
Code:
http://highered.mcgraw-hill.com/sites/0072515848/student_view0/chapter31 /powerpoint_slides.html

 
He says in page 851 :
 
"When the user client process sends a message, the proxy firewall runs a server process to receive the request. The server (I said it is the HTTP proxy )opens the packet at the application level and finds out if the request is ligitimate. If it is, the server acts as a client process and sends the message to the real server (I said it is the HTTP Sever) in the corporation. If it is not, the message is dropped and an error message is sent to the external user. Figure 31.11 shows a proxy firewall implementation".
 
Code:
http://img234.imageshack.us/img234/1307/proxyfirewallforouzanch310bc.jpg

 

 
 
If the proxy firewall can investigate (check ) the application layer by itself , why do I need to send the packet to the HTTP proxy ?

i think he's working with 2 tools (or layers). 1 proviging firwall functions and an other provides the http-based solution (fe. filtering). See 31.4, it might help to get over this issue Smiley.
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