COMPUTER NETWORKING

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NETWORK SECURITY

FIREWALLS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What do you infer from the following output?Chain INPUT (policy ACCEPT)num target prot opt source destination1 DROP all ____ 59.45.175.0/24 anywhere2 DROP all ____ 221.194.47.0/24 anywhere3 DROP all ____ 91.197.232.104/29 anywhereChain FORWARD (policy ACCEPT)num target prot opt source destinationChain OUTPUT (policy ACCEPT)num target prot opt source destination1 DROP all ____ anywhere 31.13.78.0/24
A
Input chain, forward chain and output chain are configured
B
Input chain and output chain are found no forward chain
C
Either A or B
D
None of the above
Explanation: 

Detailed explanation-1: -Default Policies Chain The default policy is ACCEPT, change the policy to DROP for all the INPUT, FORWARD, OUTPUT.

Detailed explanation-2: -The filter table in iptables has three chains (sets of rules). The INPUT chain is used for any packet coming into the system. The OUTPUT chain is for any packet leaving the system. And the FORWARD chain is for packets that are forwarded (routed) through the system.

Detailed explanation-3: -In this article, we discussed the differences between the DROP and REJECT rules while using iptables. We examined them using the INPUT chain. The REJECT rule immediately rejected the ICMP echo requests with a Destination Port Unreachable error. On the other hand, for DROP, the ICMP echo request timed out after a while.

Detailed explanation-4: -Allow SSH session to firewall 2 by using the following command: iptables-A INPUT-p tcp–dport 22-s 0/0-j ACCEPT. Allow ICMP traffic to firewall 2 by using the following command: iptables-A INPUT-p icmp-j ACCEPT. Allow all related and established traffic for firewall 2 by using the following command:

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