NAT & PAT

Configure static one-to-one NAT for two inside hosts on R1, mark inside/outside interfaces correctly, and read the four-column NAT translation table (inside local/global, outside local/global). Verify from both sides and relate observed traffic to table entries.

Configure dynamic one-to-one NAT using a public address pool on an IOS router between a private LAN and a simulated ISP. Two inside hosts draw from a two-address public pool on-demand. Validate that no translations exist before traffic, that each host receives a distinct global address after generating traffic, and that entries age out when idle.

Implement Port Address Translation (PAT) using a one-address NAT pool so multiple inside hosts share a single public IP. Reuse the same 5-node topology and addressing as the prior lab; convert the pool to a single address and enable overload. Verify simultaneous connectivity from two inside hosts, observe translations and counters, and contrast with prior pool-exhaustion behavior.

Implement and verify interface-based PAT (overload) on a single-edge SOHO router. Inside hosts on 192.168.10.0/24 share the router’s lone public IP (203.0.113.1) on its outside interface. Validate NAT translations, ACL matches, and simultaneous host access, and practice troubleshooting common misconfigurations (inside/outside role reversal, ACL selection errors).

Configure static PAT (port forwarding) on a Cisco IOS edge router so an outside client can reach an inside HTTP service on TCP/8080 using a dedicated public IP that is not the router's interface. Validate using curl from the outside host and NAT show commands on the router.

Configure PAT on an edge router so only PC-A is translated using a standard ACL as the traffic selector. PC-B remains untranslated and fails to reach the ISP, illustrating that NAT occurs only for traffic explicitly matched by the ACL. Validate using host pings and IOS show commands, and interpret ACL hit counters and NAT tables.

Build an Internet-edge NAT design that reaches beyond the ISP to a real external network. You will configure dynamic PAT (overload) from a private LAN to a public /29 using a NAT pool on the edge router, with the router’s default route already pointing to the ISP. Verify that an inside host can reach a public server across the ISP and that translations, counters, and default routing reflect the expected state.

Operate, observe, and clear Cisco IOS PAT translations on an internet edge. You will configure a standard PAT overload on R1, generate multiple concurrent sessions from an inside host, read translation/state counters, and clear single and all entries to see how the table repopulates immediately under live traffic.

Advanced NAT capstone, run as a fault hunt. Inside hosts cannot reach the internet, the translation table stays empty, and one host cannot even reach its own gateway. The lab is called NAT, which is the trap: not every fault here is a NAT fault. You get symptoms and the required end state — no fault list. Faults span the router, the switch and the path beyond, and fixing the translation alone will not restore service.