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Firewall Tutorial
• Source IP Address = 199.211.211.17
• Source IP address mask = 255.255.255.255
• Destination IP Address = 0.0.0.0
• Destination IP address mask = 0.0.0.0
• Using the tables on page 158, find the destination port and protocol numbers (the local
Telnet port):
• Protocol = TCP (or 6)
• Destination Port = 23
• The filter should be enabled and instructed to block the Telnet packets containing the
source address shown in step 2:
• Forward = unchecked
This four-step process is how we produced the following filter from the original rule: