Question

You are given the following "informal firewall policy" details to be implemented using the firewall topology illustrated in slide # 22 (Chapter 9) Present the rules for the external and internal firewalll in a table format. a) Email may be sent using SMTP in both directions through the firewall, but it must be relayed via the DMZ mail gateway. External email must be destined for the DMZ mail server. b) Users inside may retrieve their e-mail from the DMZ mail gateway, using either POP3 or POP3S c) Users outside my retrieve their email from the DMZ mail gateway, but only if they use the secure POP3 (POP3S) protocol. d) Web requests are allowed from any internal user out through the firewall but must be relayed via the DMZ Web proxy, which provides content filtering

Answer 1

Solution:-

Internal firewall:

S.no	Our Host	Port	Their host	port	comment	action
1	-	-	DMZ mail gateway	SMTP		allow
2	-	-	DMZ mail gatewaty	POP3/POP3S	Authentication	allow
3	-	-	DMZ web proxy	HTTP/HTTPS	content filtering	allow
4	-	-	-	-	block	deny

External firewall:

S.no	Our Host	Port	Their host	port	comment	action
1	DMZ mail gateway	-	-	SMTP		allow
2	-	-	DMZ mail gateway	SMTP		allow
3	-	-	DMZ mail gateway	POP3s	Authentication	allow
4	-	-			block	deny

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