When is a connection entry created on ASA for a packet that is received on the ingress interface?
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A. B. C. D. E.D.
Absolutely correct answer.
The ASA (Adaptive Security Appliance) is a network security device that provides firewall, VPN, and other security services. When a packet is received on the ingress interface of the ASA, a connection entry is created in the connection table to track the packet and its associated session.
The correct answer to the question depends on the specific circumstances of the packet and the ASA configuration. Let's examine each option in detail:
A. When the packet is checked by the access-list. An access-list is a set of rules that define what traffic is allowed or denied based on various criteria, such as source and destination addresses, protocols, and ports. When a packet is received on the ingress interface, it is checked against the access-list rules to determine whether it should be allowed or denied. If the packet matches an access-list rule, it may be subject to further processing, such as NAT (Network Address Translation) or inspection. However, creating a connection entry does not depend solely on the access-list check.
B. When the packet reaches the ingress interface internal buffer. When a packet is received on the ingress interface, it is stored in the internal buffer of the interface. The buffer is a temporary storage area where packets are held until they can be processed by the ASA. However, creating a connection entry does not depend solely on the packet being stored in the buffer.
C. When the packet is a SYN packet or UDP packet. A SYN packet is the first packet in a TCP (Transmission Control Protocol) connection, which is used to initiate a three-way handshake to establish a session between two devices. UDP (User Datagram Protocol) is a connectionless protocol that does not establish a session before transmitting data. When a SYN packet or UDP packet is received on the ingress interface, a connection entry is created in the connection table to track the session. However, this does not apply to other types of packets.
D. When a translation rule exists for the packet. Translation rules are used to change the source or destination address or port of a packet, typically for the purpose of network address translation (NAT) or port address translation (PAT). When a packet matches a translation rule, a connection entry is created in the connection table to track the translated session. However, this does not apply if there are no translation rules for the packet.
E. When the packet is subjected to inspection. Inspection is a process that examines the contents of a packet and applies security policies to the traffic based on its protocol, application, and content. When a packet is subjected to inspection, a connection entry is created in the connection table to track the session. However, this does not apply if the packet is not subject to inspection.
In summary, the correct answer to the question depends on the specific circumstances of the packet and the ASA configuration. While each option listed may contribute to the creation of a connection entry, none of them alone are sufficient to guarantee it.