Comprehensive and Detailed Explanation From Exact Extract:
To temporarily configure a Linux virtual machine as a router, the technician must enable IP forwarding and set up iptables rules to allow and masquerade traffic:
A. echo " 1 " > /proc/sys/net/ipv4/ip_forward: Enables IPv4 forwarding in the Linux kernel, allowing the VM to forward packets between interfaces.
B. iptables -A FORWARD -j ACCEPT: Adds a rule to the iptables firewall to accept all forwarded packets (allows traffic to be routed).
G. iptables -t nat -s 10.10.204.0/24 -A POSTROUTING -j MASQUERADE: Sets up network address translation (NAT) for outgoing packets from the 10.10.204.0/24 subnet, masquerading them as if they are coming from the VM’s external IP.
Other options:
C. and H. are not relevant for routing/NAT in this context (PREROUTING is generally used for DNAT, not for standard source NAT).
D. is syntactically incorrect and mixes PREROUTING with MASQUERADE, which is not the proper combination for SNAT.
E. disables forwarding.
F. is not related to IP forwarding.
[Reference:, CompTIA Linux+ Study Guide: Exam XK0-006, Sybex, Chapter 9: "Networking", Section: "Configuring Linux as a Router", CompTIA Linux+ XK0-006 Objectives: Domain 2.0 – Networking, Official CompTIA Linux+ Cert Guide, Chapter 12: “Firewall and NAT configuration”, , ]
