Multiple IKE SAs for Same Peer: Multiple Phase 2 Tunnels Established
This PCNSE practice question tests your understanding of secure access and vpn. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. A key principle to apply: iKE SA. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
admin@PA-5020> show vpn ike-sa
Gateway Peer Interface Role Life LifeKB State
GW1 10.1.1.1 ethernet1/2 Responder 86400 0 ACTIVE
GW1 10.1.1.1 ethernet1/2 Initiator 86400 0 ACTIVE
GW1 10.1.1.1 ethernet1/2 Responder 86400 0 ACTIVE
Refer to the exhibit. A network engineer sees multiple IKE SAs for the same peer. What does this indicate?
Exhibit
admin@PA-5020> show vpn ike-sa
Gateway Peer Interface Role Life LifeKB State
GW1 10.1.1.1 ethernet1/2 Responder 86400 0 ACTIVE
GW1 10.1.1.1 ethernet1/2 Initiator 86400 0 ACTIVE
GW1 10.1.1.1 ethernet1/2 Responder 86400 0 ACTIVE
A
A configuration error causes duplicate SAs.
Why wrong: Incorrect. Duplicate SAs would show identical parameters, not different roles.
B
Multiple Phase 2 tunnels are established.
Correct. Each unique proxy ID results in a separate IKE SA.
C
Multiple Phase 1 proposals are accepted.
Why wrong: Incorrect. Phase 1 negotiation results in a single SA per proposal combination.
D
The firewall is under DDoS attack.
Why wrong: Incorrect. DDoS would show many different peers, not same peer.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Multiple Phase 2 tunnels are established.
In Palo Alto firewalls, each IKE gateway configuration can result in a separate IKE SA. When you have multiple tunnel interfaces or multiple IKE gateways (e.g., with different authentication methods or local IPs) to the same peer, you will see multiple IKE SAs. Each such IKE SA corresponds to a separate Phase 1 instance, which can have its own Phase 2 SAs. Therefore, multiple IKE SAs for the same peer typically indicate that multiple tunnel interfaces or IKE gateways are configured, each establishing its own independent set of IPsec SAs. This is a normal behavior and not necessarily a misconfiguration or attack.
Key principle: IKE SA
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
A configuration error causes duplicate SAs.
Why it's wrong here
Incorrect. Duplicate SAs would show identical parameters, not different roles.
✓
Multiple Phase 2 tunnels are established.
Why this is correct
Correct. Each unique proxy ID results in a separate IKE SA.
Related concept
IKE SA
✗
Multiple Phase 1 proposals are accepted.
Why it's wrong here
Incorrect. Phase 1 negotiation results in a single SA per proposal combination.
✗
The firewall is under DDoS attack.
Why it's wrong here
Incorrect. DDoS would show many different peers, not same peer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common misconception is that multiple IKE SAs for the same peer are always a sign of misconfiguration or attack, but in Palo Alto environments, multiple IKE SAs can legitimately exist when multiple IKE gateways are configured to the same peer, each with its own Phase 2 tunnel. However, note that multiple Phase 2 tunnels with different proxy IDs under a single IKE gateway do not create extra IKE SAs; they create multiple Phase 2 SAs within the same IKE SA.
Trap categories for this question
Command / output trap
Incorrect. Duplicate SAs would show identical parameters, not different roles.
Detailed technical explanation
How to think about this question
IKEv1 maintains a single Phase 1 SA per peer pair, but multiple Phase 2 SAs can be created under it using different traffic selectors (proxy IDs). In IKEv2, multiple IKE SAs can exist between the same peers if different authentication methods or child SAs are used, but the most common scenario in PAN-OS is multiple Phase 2 tunnels. The 'show vpn ike-sa' command on Palo Alto firewalls lists each IKE SA, and multiple entries for the same peer often correspond to distinct VPN tunnels or route-based VPNs with multiple subnets.
KKey Concepts to Remember
IKE SA
Phase 2 tunnel
Proxy ID
IKE gateway
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
IKE SA
Real-world example
How this comes up in practice
A practitioner preparing for the PCNSE exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. IKE SA Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Quick reference
VPN Protocol Comparison
Protocol
Port
Encryption
Authentication
Use Case
IKEv2 / IPsec
UDP 500 / 4500
AES-256
Certificates / PSK
Site-to-site & remote access
SSL / TLS VPN
TCP 443
TLS 1.3
Certificates / MFA
Clientless remote access
L2TP / IPsec
UDP 1701
AES (IPsec)
PSK / Certificates
Legacy remote access
WireGuard
UDP 51820
ChaCha20
Public keys
Modern high-performance VPN
PPTP
TCP 1723
MPPE (weak)
MS-CHAPv2
Legacy — avoid in production
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
What to study next
Got this wrong? Here's your next step.
Review iKE SA, then practise related PCNSE questions on the same topic to reinforce the concept.
Secure Access and VPN — This question tests Secure Access and VPN — IKE SA.
What is the correct answer to this question?
The correct answer is: Multiple Phase 2 tunnels are established. — In Palo Alto firewalls, each IKE gateway configuration can result in a separate IKE SA. When you have multiple tunnel interfaces or multiple IKE gateways (e.g., with different authentication methods or local IPs) to the same peer, you will see multiple IKE SAs. Each such IKE SA corresponds to a separate Phase 1 instance, which can have its own Phase 2 SAs. Therefore, multiple IKE SAs for the same peer typically indicate that multiple tunnel interfaces or IKE gateways are configured, each establishing its own independent set of IPsec SAs. This is a normal behavior and not necessarily a misconfiguration or attack.
What should I do if I get this PCNSE question wrong?
Review iKE SA, then practise related PCNSE questions on the same topic to reinforce the concept.
What is the key concept behind this question?
IKE SA
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