How do you configure a Cisco router to allow only specific hosts access to a network? Learn how Access Control Lists (ACLs) filter traffic by IP address, protocol, and port—essential for Cisco Certified Field Technician (CCT) exam success.
Table of Contents
Question
A technician needs to configure a router to allow only specific hosts to access a network. What tool should they use?
A. Port security
B. Dynamic Host Configuration Protocol (DHCP)
C. Spanning Tree Protocol (STP)
D. Simple Network Management Protocol (SNMP)
E. Access Control Lists (ACLs)
Answer
E. Access Control Lists (ACLs)
Explanation
ACLs control traffic flow based on IP addresses, protocols, and port numbers.
The correct tool to configure a Cisco router to allow only specific hosts access to a network is Access Control Lists (ACLs).
ACLs are sets of permit and deny statements that filter network traffic based on criteria such as source or destination IP address, protocol type, and port number. They are applied to router interfaces to control which packets are allowed to enter or leave a network segment.
Standard ACLs filter traffic based only on source IP address, making them suitable for restricting access to specific hosts or entire subnets.
Extended ACLs provide more granular control, allowing filtering based on source and destination IP addresses, protocols, and port numbers.
ACLs are configured and then applied to an interface in either the inbound or outbound direction. Only traffic that matches a “permit” statement is allowed; all other traffic is denied by default due to the implicit “deny all” at the end of every ACL.
Example: To allow only host 192.168.10.5 to access a network, you might use:
access-list 10 permit 192.168.10.5 access-list 10 deny any interface GigabitEthernet0/1 ip access-group 10 in
ACLs are a fundamental security tool for controlling access and segmenting traffic within Cisco networks.
ACLs enable a router to permit or deny network access for specific hosts, subnets, or protocols, providing precise control over network security and traffic flow.
Cisco Certified Field Technician (CCT) certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the Cisco Certified Field Technician (CCT) exam and earn Cisco Certified Field Technician (CCT) certification.