Static NAT

Posted: 17th November 2020 by ccna7guru in ENSA

Now that you have learned about NAT and how it works, this topic will discuss the many versions of NAT that are available to you.

Static NAT uses a one-to-one mapping of local and global addresses. These mappings are configured by the network administrator and remain constant.

In the figure, R2 is configured with static mappings for the inside local addresses of Svr1, PC2, and PC3. When these devices send traffic to the internet, their inside local addresses are translated to the configured inside global addresses. To outside networks, these devices appear to have public IPv4 addresses.

Static NAT CCNA200-301

Static NAT is particularly useful for web servers or devices that must have a consistent address that is accessible from the internet, such as a company web server. It is also useful for devices that must be accessible by authorized personnel when offsite, but not by the general public on the internet. For example, a network administrator from PC4 can use SSH to gain access to the inside global address of Svr1 (209.165.200.226). R2 translates this inside global address to the inside local address 192.168.10.10 and connects the session to Svr1.

Static NAT requires that enough public addresses are available to satisfy the total number of simultaneous user sessions.