Networking Concepts - NAT (Network Address Translation )

Set up Cisco modeling labs via the devnet sandbox, launch a four-hour environment, install anyconnect, retrieve credentials by email, and build a topology with two CSR v1000 routers.

Build a topology in Cisco Modeling Labs by dragging CSR 1000 V router, ASA firewall, and Alpine Linux, connect gigabit interfaces, configure 10.1.1.1/24, save lab persistence, ping, and capture packets.

Understand return traffic as the reply to a packet, illustrated by a tcp acknowledgment. The five-tuple identifies flows, and return traffic swaps IPs and ports while protocol stays the same.

Represent object networks as named sets of IP addresses using individual addresses, subnets, or ranges. They simplify configuration and support applying rules in access control lists and network address translation.

Demonstrate how static NAT enforces a 1:1 mapping by changing the source address from a real IP to a mapped IP as packets cross the firewall from inside to outside.

Understand how static NAT maps a private Gmail server behind a firewall to a public IP, enabling global access while keeping private addresses hidden.

Set up the NAT lab topology, featuring the XYZ intranet behind a Cisco ASA firewall, an ISP router representing the internet, and public hosts with web and FTP servers.

Dynamic NAT uses a real IP address pool and a mapped IP pool to replace private addresses with any available public address, dropping packets when no mapped address is available.

Dynamic NAT uses a mapped IP address pool to translate private addresses to public addresses, tracks per-connection usage, and releases TCP on termination or UDP after inactivity.

Discover why PAT replaces static and dynamic NAT to save public IP addresses. See how PAT on ASA firewall lets internal resources access external networks with a shared public address.

Configure pat to let external users reach internal ftp and web servers via a single public IP, using translation on the inside and untranslation on the outside, with known ports.

Explore static NAT behavior with Cisco ASA using packet tracer: translate source IPs, keep ports constant, and observe TCP packet translation from inside to outside.

Dynamic pat translates internal private addresses to a shared public IP, using dynamic source ports and a translation table to route return traffic correctly for thousands of internal users.

Explore twice nat, where both source and destination addresses and ports translate as outbound traffic crosses the inside-outside boundary, including rerouting google dns queries to microsoft.

Explore how twice NAT on a firewall translates internal DNS queries to the Microsoft DNS server by rewriting source and destination IP addresses and ports, guided by a translation table.