GSLC · Question #561
Which of the following statements are true about an application-level gateway? Each correct answer represents a complete solution. Choose all that apply.
The correct answer is A. It allows client applications to use dynamic ephemeral TCP/UDP ports to communicate with the C. It is a security component that is added to a firewall or NAT employed in a computer network. D. It converts the network layer address information found inside an application payload. The hosts. An application-level gateway (ALG) is a security component that inspects and modifies application-layer traffic to enable NAT traversal, support dynamic port usage, and translate embedded address information within application payloads.
Question
Which of the following statements are true about an application-level gateway? Each correct answer represents a complete solution. Choose all that apply.
Options
- AIt allows client applications to use dynamic ephemeral TCP/UDP ports to communicate with the
- BIt does not allow customized NAT traversal filters to be plugged into the gateway to support
- CIt is a security component that is added to a firewall or NAT employed in a computer network.
- DIt converts the network layer address information found inside an application payload. The hosts
How the community answered
(52 responses)- A94% (49)
- B6% (3)
Why each option
An application-level gateway (ALG) is a security component that inspects and modifies application-layer traffic to enable NAT traversal, support dynamic port usage, and translate embedded address information within application payloads.
ALGs enable client applications to use dynamic ephemeral TCP/UDP ports by inspecting application-layer protocols and instructing the firewall or NAT device to open the required dynamic ports for the session.
This statement is false - ALGs are specifically architected to support pluggable, customized NAT traversal filters so that new application protocols can be handled without redesigning the gateway.
By definition, an ALG is a security component integrated into a firewall or NAT device to provide application-layer inspection and address translation beyond what basic packet filtering offers.
A core ALG function is inspecting application payloads and rewriting embedded network-layer addresses - such as IP addresses inside FTP or SIP packets - so that NAT translation remains consistent end-to-end.
Concept tested: Application-level gateway functions and NAT traversal support
Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat/configuration/15-mt/nat-15-mt-book/iadnat-alg.html
Topics
Community Discussion
No community discussion yet for this question.