Exam SY0-601 topic 1 question 385 discussion

sooo....I'm the only one who never heard of iptables?

The BEST option to remove the rules in this scenario would be option B, which is to use the command "iptables -F" to flush all the rules in the firewall. Option A ("iptables -t mangle -X") would only remove the mangle table rules, which may not be the only rules causing the issue. Option C ("iptables -Z") would zero the counters for all rules, but would not remove the rules themselves. Option D ("iptables -P INPUT -j DROP") would set the default policy of the INPUT chain to DROP, which would still cause all connections to be dropped by the firewall. Therefore, option B is the most appropriate command to remove all rules from the firewall and restore network connectivity.

Option A: deletes all user-defined chains in the mangle table, but default chains in the filter table will not be affected. Option B: This will delete all chains in all tables. Option C: this will reset the packet and byte counters Option D: Drops all incoming packets to the local host if none of the preceding firewall rules was matched, outgoing packets are not affected. None of the firewall rules are dropped either.

Where is this on the exam objectives?

These questions are all absolute garbage. iptables is mentioned in the official Sec+ material, but the -F switch is NOT covered. That they are going to ask questions about material they did NOT present to you is absurd.

The rules the person created are likely what is causing the issue. -F will flush them.

Yay, absolute lucky guess FTW

Again, I dont think this question will count on the exam if you see it as it seems to be taken from Linux+ but anyway.. "The tool you use to view and alter the chains and filters in the iptables service is the iptables command. Table 18.2 shows the commonly used iptables command-line options.... ...-F [ chain ] Removes (flush) all rules from this chain. If chain is not specified, remove all rules from all chains." -Comptia Linux+ Study Guide XK0-005 by Richard Blum & Christine Bresnahan

The command "iptables -F" flushes all the rules in the filter table, which is the default table used by iptables. This will remove all the rules and allow all traffic to pass through the firewall without any filtering or blocking. By using this command, you can effectively clear the existing rules and restore connectivity to the network.

iptables -F flushes the rules of a chain. http://explainshell.com/explain? cmd=iptables+-F. -F, --flush [chain] Flush the selected chain (all the chains in the table if none is given). This is equivalent to deleting all the rules one by one.

Is this a type of food or something?

i have never seen iptables

The BEST option to remove the rules in this scenario would be option B: # iptables -F. This command would flush all of the rules that have been created and restore the default policies. This would allow all traffic to flow through the firewall, effectively disabling it. Option A: # iptables -t mangle -X would delete all of the user-defined chains in the mangle table, which may not be necessary for removing the rules that caused the network to become unresponsive. Option C: # iptables -Z would reset the packet and byte counters for all of the chains, but would not remove any rules. Option D: # iptables -P INPUT -j DROP would set the default policy for the INPUT chain to DROP, which would drop all incoming traffic. This would not remove any rules, and would not be the best option to restore network connectivity.

B. is the correct answer. https://phoenixnap.com/kb/iptables-delete-rule

The best option to remove the rules is B. # iptables -F. The "-F" flag will flush all the existing iptable rules, allowing for a fresh start. This should help get the network back online and allow the administrator to start creating new rules that will not cause any network disruption.

C. It's not zero day. It's extremely unlikely that a vulnerability scanner would find a zero day vulnerability, bcs nobody knows it exists.

B. # iptables -F https://www.cyberciti.biz/tips/linux-iptables-how-to-flush-all-rules.html Procedure to flush and delete ALL iptables firewall rules To flush the selected chain (or all the chains in the table if none is given) pass the --flush or -F option. This is equivalent to deleting all the iptables rules one by one on Linux