ip nat inside source static
Configures a permanent, bi-directional 1:1 static translation between an internal private IP address and an external public IP address. This allows an internet user to initiate a connection directly to an internal server hidden behind your edge infrastructure.
Quick Reference
Router(config)#(Inbound + Outbound)(Never expires from RAM)no ip nat inside source static [local] [global]Syntax Breakdown
Unlike dynamic NAT configurations, which map external space on-demand using a pool of available public addresses, a static entry remains locked inside the translation memory table even if zero traffic is moving across the router.
[inside-local-ip]
The actual private RFC 1918 IPv4 address assigned directly to the internal host network adapter card (e.g., your database or web server sitting in a DMZ environment).
[inside-global-ip]
The officially routed, public-facing IPv4 address provided by the ISP that internet clients target to interact with your application over the public web interface.
CLI Deployment Scenarios
Scenario 1: Publishing an Internal Web Server
You have a web server sitting inside your LAN at 192.168.1.10. You must map it to your assigned public IP address 203.0.113.5 and designate your routing vectors.
CCNA Exam Gotchas
The Boundary Vector Trap
Even if your configuration strings for ip nat inside source static are completely flawless, NAT will fail entirely if you forget to step into interface configuration mode and type ip nat inside on your local gateway interface and ip nat outside on your internet interface. The router relies on these boundary vectors to trigger the packet re-writing engine.
Local vs. Global Terminology
The CCNA will challenge your ability to distinguish between these four exact terms:
• Inside Local: The private address of the host inside your network (e.g., 192.168.1.10).
• Inside Global: The public address that the host is translated to as it leaves the router (e.g., 203.0.113.5).
• Outside Global: The real public IP address belonging to the foreign host on the internet.
• Outside Local: The local name tracking that foreign host (almost always matches the Outside Global IP address).