5 Network Security Fundamentals Free Online FlashCards

What three goals does network security protect?

Network security protects the confidentiality, integrity, and availability of data and services.

How are ACL entries evaluated?

ACL entries are checked in order, and processing stops at the first match. If no entry matches, the implicit final rule denies the traffic.

How do standard and extended IPv4 ACLs differ?

A standard IPv4 ACL matches the source address only. An extended ACL can also match destination address, protocol, and applicable TCP or UDP ports.

What do 0 and 1 mean in an ACL wildcard mask?

In a wildcard mask, 0 means the address bit must match and 1 means it is ignored. The mask 0.0.0.255 matches a /24 network.

Where are extended and standard ACLs often placed?

Extended ACLs are commonly placed near the traffic source to stop unwanted traffic early. Standard ACLs are often placed closer to the destination because they cannot match destinations.

Why prefer SSH and HTTPS for device management?

Prefer SSH over Telnet and HTTPS over HTTP for management because Telnet and HTTP do not protect credentials and sessions in transit.

What do authentication, authorization, and accounting each do?

Authentication verifies identity, authorization determines what an authenticated user may do, and accounting records user activity.

What does DHCP snooping do?

DHCP snooping blocks unauthorized DHCP server messages on untrusted ports and builds a binding table with client details such as IP address, MAC address, VLAN, and switch port.

How does Dynamic ARP Inspection help protect a network?

Dynamic ARP Inspection checks ARP messages on untrusted interfaces against IP-to-MAC bindings and drops invalid messages, helping defend against ARP spoofing and poisoning.

What does switch port security control?

Port security limits which source MAC addresses may use a switch port. It can set a maximum, specify allowed addresses, or use sticky learning where supported.

What threat does RA Guard help prevent?

RA Guard filters unauthorized IPv6 Router Advertisement messages on Layer 2 ports, helping prevent a rogue host from advertising itself as a router.

How do site-to-site and remote-access VPNs differ?

A site-to-site VPN connects networks through gateways. A remote-access VPN connects an individual user's device to an organization's network, often using client software and user authentication.