Cisco CCNA (200-301) — All Questions

A network uses Port Address Translation (PAT). How does the router distinguish return traffic for multiple internal hosts sharing one public IP address?

• a.By using unique source port numbers✓
• b.By using different MAC addresses
• c.By assigning each host a separate public IP
• d.By using VLAN tags

PAT (NAT overload) maps many private addresses to a single public IP by translating and tracking unique source port numbers for each session. The router records these port-to-host mappings in its translation table so return traffic is delivered to the correct inside host. This conserves scarce public IPv4 addresses.

Which protocol synchronizes the clocks of network devices so that log timestamps and certificates remain consistent?

• a.SNMP
• b.Syslog
• c.DNS
• d.NTP✓

NTP (Network Time Protocol) synchronizes device clocks to a reliable time source, typically over UDP port 123. Accurate time is essential for correlating Syslog messages, validating certificates, and troubleshooting. Devices reference a stratum hierarchy where lower stratum numbers are closer to the authoritative time source.