H12-711_V4.0 HCIA-Security V4.0 Exam Questions and Answers

Explanation From HCIA-Security documents:

TCP is a connection-oriented transport protocol, so it must establish a reliable session before user data can be exchanged. To create the session, TCP uses the three-way handshake: the initiator sends a SYN to request a connection and advertise its initial sequence number, the responder replies with SYN/ACK to acknowledge the request and provide its own initial sequence number, and finally the initiator sends an ACK to confirm receipt. This process confirms bidirectional reachability, synchronizes sequence numbers, and prepares both ends for reliable delivery, retransmission control, and flow control.

To end a TCP connection gracefully, TCP performs an orderly close in both directions (full-duplex). One endpoint sends FIN to indicate it has no more data to send, the peer responds with ACK . When the peer is also ready to stop sending, it transmits its own FIN , and the original endpoint responds with a final ACK . Because each direction is closed independently, termination is typically described as a four-way handshake .

Explanation From HCIA-Security documents:

Portal authentication is an identity-based access control method where a user is redirected to an authentication portal and, after successful login, is permitted to access network resources based on the configured policy. The key point is that the authentication page is not limited to the firewall’s built-in page only. In Huawei Portal solutions, the authentication page can be provided by the device itself or by an external Portal server, and the user completes authentication on the presented Portal page after redirection. Therefore, saying users can be authenticated only on the firewall authentication page is incorrect.

The other statements describe the two common triggering modes correctly. In session authentication, the user accesses an HTTP service first, is redirected or challenged, and service access is permitted only after identity authentication succeeds. In user-initiated authentication, the user proactively opens the authentication page and logs in first, then gains access to network resources. These are recognized built-in triggering modes for Portal authentication.

A firewall is primarily a boundary security device used to control traffic between networks of different trust levels, such as an intranet and an extranet or the Internet. Its key capability is enforcing access control based on security policies, which helps prevent unauthorized traffic and information flows from less trusted networks into more trusted ones. That is why statement B is correct: by applying security policies, the firewall can block unauthorized access attempts and prevent unapproved data from the extranet reaching intranet resources.

The other statements are incorrect because they overstate firewall capabilities. A firewall alone cannot guarantee protection against zero-day vulnerabilities, because zero-days may not match known signatures or rule patterns, and prevention often requires multiple layers such as endpoint hardening, behavioral detection, and timely patching. It also cannot defend against all external threats, since attacks can bypass controls through encrypted traffic, insider misuse, misconfigurations, or compromised endpoints. Even if a firewall supports antivirus features, it does not replace endpoint and network antivirus deployment; layered security is still required.

By default, a firewall’s security policy is mainly used to control unicast traffic between security zones. Unicast packets are the normal one-to-one communication packets exchanged between a single source host and a single destination host. Because most user service traffic, such as web access, file transfer, remote login, and application communication, is carried in unicast form, firewall security policies are primarily designed to inspect and control this type of traffic.

Broadcast packets are typically used for local network discovery or service announcements within the same broadcast domain, and they are not the standard focus of interzone security policy control. Multicast traffic is one-to-many communication and usually requires additional multicast-specific handling or routing mechanisms rather than ordinary default security policy treatment. Anycast is a special addressing and routing method rather than the usual packet-control category emphasized in firewall default policy behavior.

In Huawei firewall policy design, when administrators configure permit or deny rules between zones, those rules are generally intended to manage unicast service traffic . Therefore, among the options listed, the packet type controlled by a firewall’s security policy by default is Unicast .

Explanation From HCIA-Security documents:

A packet filtering firewall mainly makes decisions based on L3/L4 header information such as source/destination IP address, protocol, and port, usually through static ACL rules . Because it does not deeply understand application behavior and typically does not track full session state like a stateful inspection firewall, it has several limitations.

A is a disadvantage because basic packet filtering is often implemented as rule-by-rule matching; under heavy traffic or intentionally flooded traffic, performance can degrade and the device may be pressured by DoS-style loads, especially if rules are long or the platform is resource-limited.

B is also a disadvantage: packet filtering that trusts only IP information can be bypassed by IP spoofing in certain scenarios, allowing traffic to appear as if it comes from an allowed address.

C is correct because packet filtering relies on static policies , which struggle to handle dynamic connections, complex services, and fine-grained user-based control.

D is not a disadvantage of packet filtering; dynamic connection status lists are a feature of stateful firewalls, not simple packet filters.

Explanation From HCIA-Security documents:

PKI is mainly used where digital certificates are needed to prove identity, distribute public keys safely, and support functions such as authentication, encryption, and digital signatures . HTTPS web login relies on server certificates (and sometimes client certificates) to build trust and establish encrypted sessions, so D is a classic PKI scenario. SSL VPN also typically uses certificates for gateway identity and often for user/device authentication, so A fits PKI usage as well. IPv6 SEND Secure Neighbor Discovery uses cryptographic mechanisms (such as CGA and signature-based protection) that depend on certificates, making C another PKI-related scenario.

By contrast, IPsec VPN does not necessarily depend on PKI in all deployments. IPsec can authenticate peers using pre-shared keys or other methods without certificates, so it is commonly treated as not strictly a PKI application scenario in basic classification questions. In many training outlines, PKI scenarios are highlighted as HTTPS, SSL VPN, and IPv6 SEND, while IPsec is presented as a separate VPN technology that may or may not integrate certificates. Therefore, the best answer is B .

Explanation From HCIA-Security documents:

Antivirus software relies heavily on its signature database to identify known malware, suspicious files, and malicious behaviors. Because new threats appear continuously and existing malware is frequently modified to evade detection, the signature library must be updated very often to keep protection effective. Updating every day is the best practice in most enterprise and personal environments, and many antivirus products actually update multiple times per day automatically.

If signatures are updated only monthly , half-monthly , or every three months , there is a large window where newly released malware samples and variants will not be recognized, increasing the chance of infection and successful compromise. Daily updates reduce this exposure window and ensure the antivirus engine has the newest detection patterns, reputation indicators, and sometimes updated heuristic rules released by the vendor.

In addition, daily updates align with operational security expectations: endpoints are exposed to internet content, email attachments, removable media, and downloads on a constant basis, so outdated signatures quickly become a weak link. Therefore, the correct answer is Every day .

Explanation From HCIA-Security documents:

IPsec secures user traffic mainly through the ESP or AH mechanisms, delivering a combination of confidentiality and authentication-related protections. Data encryption (A) provides confidentiality so that intercepted packets cannot be read by unauthorized parties. This is typically delivered by ESP using symmetric encryption algorithms negotiated during IKE.

For authentication, IPsec provides data origin authentication (B) , meaning the receiver can confirm that packets were generated by the expected peer (the holder of the correct IPsec SA and keys). Along with that, IPsec performs a data integrity check (D) so that any modification to the protected portion of a packet in transit is detected; integrity is commonly provided using an HMAC or authenticated encryption method.

Finally, IPsec also includes anti-replay (C) protection. By using sequence numbers and a replay window, the receiver can detect and discard duplicated old packets, which prevents attackers from capturing encrypted/authenticated traffic and retransmitting it to disrupt sessions or attempt misuse.

Because IPsec secure transmission depends on encryption plus authentication, integrity, and replay protection working together, all four options are correct.

This statement is TRUE . HTTPS is essentially HTTP running over TLS . While HTTP by itself transmits data in plaintext, HTTPS adds the TLS security layer to protect communication between the client and the server. By introducing TLS, HTTPS provides three important security functions during transmission.

First, it provides identity authentication . The server proves its identity to the client through a digital certificate , helping the client confirm that it is communicating with the legitimate server rather than an attacker. Second, HTTPS provides encryption . After the TLS negotiation process is completed, the transmitted HTTP data is encrypted, preventing attackers from easily reading sensitive information such as usernames, passwords, and session data. Third, HTTPS ensures data integrity . TLS includes mechanisms to detect whether transmitted data has been modified during communication.

Because of these features, HTTPS is widely used for secure web access, online transactions, authentication pages, and confidential information exchange. Therefore, the statement that HTTPS introduces the TLS layer based on HTTP to provide authentication, encryption, and integrity protection is correct.

A Denial of Service attack is intended to make a host, server, or network service unavailable to legitimate users. It usually works by exhausting system resources such as bandwidth, CPU, memory, connection tables, or buffers, so valid users cannot access the service normally. Therefore, statement B is correct because the essential purpose of a DoS attack is to interrupt services or block resource access on the target.

Statement C is also correct. Many DoS attacks attempt to consume queue space, session resources, or buffers on the target so that new connection requests cannot be processed. This is a common way of making a service unavailable. Statement A can also be correct in the context of some DoS methods, because attackers may use IP spoofing to hide their identity, bypass simple filtering, or increase the difficulty of tracing the attack source.

Statement D is incorrect because DoS attacks are designed to affect availability , not to create unrecoverable physical damage to hardware. They may crash systems, overload services, or interrupt access, but they do not normally destroy the target device physically.

Explanation From HCIA-Security documents:

The statement is incorrect for two reasons. First, in asymmetric cryptography, encryption and decryption are not restricted to only “public encrypt, private decrypt.” That is one common confidentiality use case (for example, encrypting a session key so only the holder of the matching private key can recover it). However, asymmetric key pairs are also used the other way around for digital signatures : the sender uses the private key to generate a signature (often described conceptually as “private-key operation”), and others use the public key to verify it. So it’s not true that “only public keys can be used to encrypt data” in all cases or contexts.

Second, calling the process “irreversible” is misleading. Asymmetric encryption is designed to be reversible for authorized parties : ciphertext can be decrypted with the corresponding key (private key for public-key encryption). What is “one-way” is the practical difficulty of recovering the plaintext without the correct key. Therefore, the correct choice is FALSE .

Explanation From HCIA-Security documents:

AAA provides a unified framework for Authentication, Authorization, and Accounting, and on Huawei devices the AAA authentication method can be selected according to the management and deployment requirements. Local authentication uses user accounts stored on the device itself, which is suitable for small environments, emergency access, or when external servers are unavailable. RADIUS authentication relies on a centralized RADIUS server, commonly used for large-scale user access control and unified credential management. HWTACACS authentication is another centralized mode that supports fine-grained control and is often preferred in scenarios requiring stronger separation of authentication and authorization, as well as detailed command-level management in some deployments. In addition, AAA can be configured for no authentication (also called none), meaning the device does not verify user identity for a specific access scenario. This mode is typically used only in controlled environments or for specific services where authentication is handled elsewhere, because it reduces security. Therefore, all listed modes are supported by AAA.

Explanation From HCIA-Security documents:

In the TCP/IP and OSI reference models, the transport layer is responsible for end-to-end communication between hosts. It provides services such as segmentation, multiplexing through port numbers, and (depending on the protocol) reliability, flow control, and congestion control. The two core transport layer protocols are TCP and UDP.

TCP is connection-oriented and reliable: it establishes a session using the three-way handshake, uses sequence numbers and acknowledgments for retransmission, and supports flow and congestion control to ensure ordered delivery. UDP is connectionless and best-effort: it does not build a session or guarantee delivery, which makes it lightweight and suitable for scenarios such as voice/video streaming and simple query/response services.

By contrast, FTP and DHCP are application layer protocols. FTP provides file transfer services and runs over TCP ports, while DHCP provides dynamic IP address assignment and uses UDP at the transport layer but is itself an application-layer protocol. Therefore, the transport-layer protocols in the options are UDP and TCP.

Explanation From HCIA-Security documents:

L2TP is a Layer 2 tunneling protocol designed to carry PPP frames across an IP network by encapsulating them inside L2TP tunnels. That’s why statement B is correct: L2TP’s job is to transport PPP traffic through a tunnel between an L2TP Access Concentrator and an L2TP Network Server. In typical remote-access VPN use, employees connect from outside (hotel, home, mobile network) and reach internal resources through the VPN, so A and D match common deployment scenarios.

The incorrect statement is C because PPP is not routable over the public Internet by itself. PPP was originally meant for point-to-point links (like dial-up or serial links). On an IP network such as the Internet, PPP frames must be encapsulated by a method like L2TP (often paired with IPsec for confidentiality and integrity) or converted via technologies such as PPPoE/PPPoA for specific access networks.

The correct operation is D because email attachments are a common carrier for malware, phishing payloads, ransomware, Trojans, and malicious scripts. In enterprise security practice, a user should not trust an attachment only because the message looks work-related or appears to come from a company mailbox . Attackers can spoof sender information, disguise malicious content, or compromise legitimate accounts. Therefore, simply checking the content or sender is not enough to ensure safety.

A safer process is to verify the sender and the email details carefully , such as the address, subject, wording, unexpected urgency, and whether the attachment type matches the business context. After that, the attachment should be scanned with antivirus or endpoint security software before opening or saving it. This helps detect known malicious files and reduces the chance of infecting the host or internal network.

Option A is unsafe because work relevance alone does not prove the file is harmless. B is clearly wrong because attachments can directly affect information security. C is also unsafe because internal-looking mail can still be malicious. Therefore, D is the correct answer.

Explanation From HCIA-Security documents:

In ESP transport mode, the authentication function provides data integrity and origin authentication for specific parts of the IP packet. The authentication calculation covers the ESP header, TCP/UDP header, user data, and ESP tail (including padding, Pad Length, and Next Header fields) . However, it does not include the outer IP header, because some IP header fields (such as TTL) may change during packet forwarding. It also does not include the ESP Authentication Data field itself, since that field stores the integrity check value result of the calculation.

In the diagram, range 3 correctly represents the portion starting from the ESP header up to the ESP tail, excluding the IP header and excluding the ESP Authentication Data field.

Range 1 only covers part of the payload, range 2 does not include the ESP header, and range 4 incorrectly includes the IP header. Therefore, option 3 accurately describes the authentication scope of ESP in transport mode.

Explanation From HCIA-Security documents:

HTTPS protects web-based management by combining encryption with server identity authentication . For the browser to trust the device’s HTTPS service, the device must present a server certificate that can be validated by the browser. That is why administrators often configure the device to use a local certificate (the device’s certificate) that is issued by a trusted CA or whose CA chain has been imported into the browser/OS trust store. When the certificate is trusted, the browser can verify the certificate chain, validity period, and hostname binding, which helps prevent attackers from impersonating the device during login.

If a device uses a self-signed or untrusted certificate, the browser shows warnings and users may click through them, increasing the risk of man-in-the-middle attacks and credential theft. Using a CA-trusted certificate strengthens administrator logins by ensuring the management page you connect to is genuinely the intended device and that the session is encrypted end-to-end.

Certificate application

Certificate issuing

Certificate storage

Certificate verification

Certificate usage

Certificate update

Certificate revocation

The PKI lifecycle describes the complete process a digital certificate goes through from creation to termination. The first stage is certificate application , where a user or device generates a key pair and submits a certificate request to the certification authority or registration authority.

After the request is approved, the CA performs certificate issuing , which involves creating and signing the certificate using the CA’s private key. Once issued, the certificate must be securely saved on the device, which is the certificate storage phase. Proper storage ensures that the certificate and the associated private key can be safely used when authentication or encryption is required.

Before using a certificate in communication, systems perform certificate verification . This step checks the certificate chain, validity period, and CA signature to confirm that the certificate is trustworthy. After successful verification, the certificate enters the certificate usage phase, where it is used for encryption, authentication, digital signatures, or secure communications such as HTTPS or IPsec.

During its lifetime, a certificate may require certificate update (renewal) when it approaches expiration. Finally, if the certificate becomes invalid or compromised, certificate revocation is performed to terminate its trust before its expiration date.