The provided ACL configuration rule 5 permit source 172.16.105.2 0 uses a basic ACL (number 2000) to explicitly permit traffic originating from the single host IP address 172.16.105.2. The wildcard mask 0 is equivalent to a host mask of 0.0.0.0, ensuring an exact match for only that source IP. Crucially, all Huawei ACLs have an implicit deny any rule at the end. When this ACL is applied to filter incoming traffic on the Telnet (VTY) interface, it will permit connection attempts from 172.16.105.2 and, due to the implicit deny, block connection attempts from all other source IP addresses.

The option 'False' is incorrect. It might be chosen by someone forgetting the implicit deny any rule that is appended to every ACL. Without this implicit rule, the ACL would only permit the specified host but would not explicitly block others, which is not how ACLs function. The combination of the explicit permit and the implicit deny creates a "whitelist" policy.

1. Huawei HCIA-Datacom V1.0 Training Material, "Configuring a Basic ACL", Section: Applying an ACL to a VTY Interface to Control Login Users. (This section provides examples of using basic ACLs to restrict Telnet/SSH access).

2. Huawei VRP V800R012C10 Configuration Guide - Security, "ACL Configuration", Section: Default ACL Rule. (This document explicitly states that "By default, an implicit deny rule exists at the end of each ACL to deny all packets that do not match any rule in the ACL.").

3. Huawei HedEx Documentation for NE40E Routers, "ACL Configuration", Section: Configuring a Basic ACL. (This documentation confirms that a wildcard mask of 0 matches a specific host).