A network administrator is reviewing the fundamental operation of standard IPv4 Access Control Lists (ACLs) on a Cisco IOS router. Which two statements correctly describe the operational characteristics of standard IPv4 ACLs?
- Standard IPv4 ACLs filter network traffic based solely on the source IPv4 address.Cevap
- Traffic that does not match any explicit permit or deny rule in the ACL is dropped by an implicit deny entry.Cevap
- CUnmatched packets are automatically permitted and forwarded out the interface by default.
- DStandard IPv4 ACLs inspect Layer 4 TCP and UDP port numbers to restrict specific application traffic.
Cevap
The correct statements are that standard IPv4 ACLs filter traffic based strictly on source IPv4 addresses, and that unmatched packets are dropped due to the implicit deny statement at the end of the list.
Standard IPv4 ACLs make forwarding or dropping decisions based exclusively on the packet's source IPv4 address. Additionally, any traffic that does not match an explicit rule in the list is dropped automatically by the default implicit deny clause at the end of the ACL.
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Standard IPv4 ACL Filtering Scope and Implicit Deny Mechanism