Which technology maps private IP addresses to public addresses to enable Internet access for internal hosts?

Which technology maps private IP addresses to public addresses to enable Internet access for internal hosts?

• A. Network Address Translation (NAT)
• B. Proxy caching
• C. VLAN tagging
• D. DNSSEC

Answer: (A)

Mapping private IP addresses to public addresses to allow internal hosts to reach the Internet is done by Network Address Translation. NAT translates the private IP (and often the source port) of outbound packets into a public IP address (and a new port), and it keeps a translation table so return traffic can be directed back to the correct internal device. This setup hides internal addressing, conserves public IP space, and lets multiple devices share a single or limited set of public IPs through port multiplexing (often referred to as PAT when a single public IP is used). Other options don’t fit this function: proxy caching stores copies of web content to speed up retrieval, VLAN tagging deals with segmenting networks at Layer 2, and DNSSEC adds authentication to DNS responses.

Mapping private IP addresses to public addresses to allow internal hosts to reach the Internet is done by Network Address Translation. NAT translates the private IP (and often the source port) of outbound packets into a public IP address (and a new port), and it keeps a translation table so return traffic can be directed back to the correct internal device. This setup hides internal addressing, conserves public IP space, and lets multiple devices share a single or limited set of public IPs through port multiplexing (often referred to as PAT when a single public IP is used).

Other options don’t fit this function: proxy caching stores copies of web content to speed up retrieval, VLAN tagging deals with segmenting networks at Layer 2, and DNSSEC adds authentication to DNS responses.