We have an internal webserver, used only for testing purposes, at IP address 5.6.7.8 on our internal corporate network. The pack
et filter is situated at a chokepoint between our internal network and the rest of the Internet. Can such a packet filter block all attempts by outside hosts to initiate a direct TCP connection to this internal webserver? If yes, design suitable packet filter rule sets (similar to those shown in the table below) that provides this functionality; if no, explain why a (stateless) packet filter cannot do it.
Table: Packet-Filtering Examples
Rule, Direction, Src address, Dest addresss, Protocol, Dest port, Action
1, In, External, Internal, TCP, 25, Permit
2, Out, Internal, External, TCP, >1023, Permit
3, Out, Internal, External, TCP, 25, Permit
4, In, External, Internal, TCP, >1023, Permit
5, Either, Any, Any, Any, Any, Deny
Table: Packet-Filtering Examples
Rule, Direction, Src address, Dest addresss, Protocol, Dest port, Action
1, In, External, Internal, TCP, 25, Permit
2, Out, Internal, External, TCP, >1023, Permit
3, Out, Internal, External, TCP, 25, Permit
4, In, External, Internal, TCP, >1023, Permit
5, Either, Any, Any, Any, Any, Deny
1 answer:
Answer:
Check the explanation
Explanation:
A packet filter firewall is used as a check point between internal corporate network to the outside internet. It blocks all the inbound traffic from the outside hosts trying to initiate a direct TCP connection to the internal corporate webserver. The network design with firewall is shown in the attached image below:
The figures in the attached image below shows an internal corporate network is protected with a packet filter firewall to minimize the inbound traffic from the external network or an internet. Therefore, the packet filter is used as a check point between the network.
The packet filter blocks all attempts by the outside hosts in order to initiate a direct TCP connection to the internal webserver of the internal corporate network.
Going by the second part of the attached image below can can therefore conclude that:
• Rule 1 specifies that, deny any packet with the destination address 5.6.7.8 if the STN flag of TCP header is set.
• Rule 2 specifies that, allow the inbound email traffic from the external source.
• Rule 3 specifies, allows the Outbound TCP traffic from the internal corporate network.
• Rule 4 specifies, allows outbound Email traffic from the internal corporate network to the external network.
• Rule 5 specifies, block any traffic from any source to the any destination.
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Answer:
Explanation:
The following Python code creates all of the necessary functions in order to request and validate all of the inputs from the user. Once everything is entered and validated it calculates the total fee and outputs it to the user. Also calls the entire class at the end using a test variable...
class Customer:
library_card = 0
patrons_name = ""
patrons_address = ""
type_of_book = ""
book_title = ""
days_overdue = 0
fee = 0.0
book_list = ['paperback regular', 'paperback best seller', 'magazine', 'hardcover']
def __init__(self):
self.library_card = self.get_library_card()
self.patrons_address = input("Patron's Address: ")
self.book_title = input("Book Title: ")
self.type_of_book = self.get_type_of_book()
self.days_overdue = float(self.get_days_overdue())
self.calculate_total()
print("Your total Fee is: " + str(self.fee))
def get_library_card(self):
library_card = int(input("Enter 4-digit library card number: "))
if (type(library_card) == type(0)) and (len(str(library_card)) == 4):
return library_card
else:
print("Invalid Card number:")
self.get_library_card()
def get_type_of_book(self):
type_of_book = input("Type of Book 1-4: ")
if (int(type_of_book) > 0) and (int(type_of_book) <= 4):
return int(type_of_book)
else:
print("Invalid Type")
self.get_type_of_book()
def get_days_overdue(self):
days_overdue = input("Number of Days Overdue: ")
if int(days_overdue) >= 0:
return days_overdue
else:
print("Invalid number of days")
self.get_days_overdue()
def calculate_total(self):
if self.type_of_book == 1:
self.fee = 0.20 * self.days_overdue
if self.fee > 8:
self.fee = 8
elif self.type_of_book == 2:
self.fee = 0.50 * self.days_overdue
if self.fee > 15:
self.fee = 15
elif self.type_of_book == 3:
self.fee = 0.25 * self.days_overdue
if self.fee > 5:
self.fee = 5
else:
self.fee = 0.30 * self.days_overdue
if self.fee > 23:
self.fee = 23
test = Customer()
