In an OpenVPN bridged (tap) setup, what is the purpose of bridging the tap interface with a physical Ethernet interface?

To enable NAT for VPN clients to access the internet.

To provide a separate IP subnet for VPN clients.

To route IP traffic between the VPN and the LAN at Layer 3.

To allow VPN clients to appear as if they are directly connected to the physical LAN.

Two Linux gateways are configured for a site-to-site IPsec VPN using racoon and setkey. The tunnel was working, but after a network change, it stopped. The administrator runs `setkey -D` on both gateways and sees no SAs. Running `racoon -F` on the initiating gateway shows: `phase1 negotiation failed.` Which of the following is the most likely cause?

The ESP protocol is blocked by a firewall on the receiving gateway.

The `spdadd` command used `ah` instead of `esp` on one gateway.

The SPD on the receiving gateway does not match the traffic, so it drops the IKE packets.

The pre-shared keys on the two gateways are different.

Which firewall rule is commonly needed on an OpenVPN server to allow VPN clients to access the internet?

iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE

iptables -A INPUT -p udp --dport 1194 -j DROP

iptables -A FORWARD -i tun0 -o tun0 -j ACCEPT

iptables -A INPUT -i tun0 -j REJECT

What is the primary difference between OpenVPN's tun and tap modes?

tun is for bridged networking and tap is for routed networking.

tun operates at Layer 3 (routed) and tap operates at Layer 2 (bridged).

tun is faster but less secure, while tap is slower but more secure.

tun is used for client-to-site VPNs, while tap is used for site-to-site VPNs.

LPIC-3 Security

Domain 4Objective 4

328.4 Virtual Private Networks (weight: 4) LPIC-3-SECURITY Practice Questions (Page 4)

Part of the Topic 328: Network Security domain, which makes up ~27% of our current practice bank. Linux Professional Institute does not publish an official question count, but from its 90-minute exam (~35–60 total, ~9–16 in this domain), expect 2–4 from this objective — we provide 30 practice questions to prepare you well beyond it. (estimate)

30questions here

6free pages

12concepts

Questions 16–20

16foundation · easy
In an OpenVPN bridged (tap) setup, what is the purpose of bridging the tap interface with a physical Ethernet interface?
Select an answer first
17expert · hard
Two Linux gateways are configured for a site-to-site IPsec VPN using racoon and setkey. The tunnel was working, but after a network change, it stopped. The administrator runs `setkey -D` on both gateways and sees no SAs. Running `racoon -F` on the initiating gateway shows: `phase1 negotiation failed.` Which of the following is the most likely cause?
Select an answer first
18foundation · easy
Which firewall rule is commonly needed on an OpenVPN server to allow VPN clients to access the internet?
Select an answer first
19foundation · easy
In an IPsec server setup for a routed VPN, which kernel feature must be enabled to allow remote clients to reach the LAN?
Select an answer first
20foundation · easy
What is the primary difference between OpenVPN's tun and tap modes?
Select an answer first

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328.4 Virtual Private Networks (weight: 4) LPIC-3-SECURITY Practice Questions (Page 4)

Questions 16–20

In an OpenVPN bridged (tap) setup, what is the purpose of bridging the tap interface with a physical Ethernet interface?

Which firewall rule is commonly needed on an OpenVPN server to allow VPN clients to access the internet?

In an IPsec server setup for a routed VPN, which kernel feature must be enabled to allow remote clients to reach the LAN?

What is the primary difference between OpenVPN's tun and tap modes?

Keep studying — Topic 328: Network Security