OSPF (Open Shortest Path First) is an interior gateway protocol (IGP) used to exchange routing information between routers in an autonomous system (AS) to determine the shortest path and ensure that packets arrive quickly from the source destination.
NAT (Network Address Translation) is a technology that converts private IP addresses into public IP addresses, enabling private networks to access the Internet. NAT is implemented on the router, and the private IP address is mapped to the public IP address by modifying the IP address and port number in the header of the data packet on the router.
Combining these two technologies saves IP address resources by converting private IP addresses to public IP addresses. At the same time, OSPF can implement efficient routing in large enterprise networks to ensure that data packets can reach their destinations quickly.
1. Experimental environment:
S1, S2, and R3 establish adjacency relationships through OSPF, and import direct routes at the same time. R3 uses dynamic NAT to convert external network addresses to internal network addresses, so that external network users can access the internal network, and internal network users cannot access external network users.
2. Create the following topology:
3. S1 S2 R3 PC1 PC2 PC3 basic interface address configuration:
S1 configuration:
S1(config)# interface Loopback0 //配置环回地址，默认为本设备router-id
S1(config-if)# ip address 1.1.1.1 255.255.255.255
S1(config)# interface Ethernet0/0
S