The cisco 2621 router networking configuration command uses the cisco2621 router to form a small LAN, note: Configure command 1, configure the access password conf tenable secret flw521521line vty 0 4 password Authentication service password-encryption limit 2, configure interface IP enableconf tinter fa0/0ip address 192.168.2.2 255.255.255.0no shutdown inter fa0/ 1ip address 192.168.20.1 255.255.255.0no shutdown 3. Add the default route conf tip route 0.0.0.0 0.0.0.0 192.168.2.1 www.2cto.com 192.168.2.1, which is actually the gateway ip address, according to the needs of the environment, you can also switch to interface 4, configure DNS conf tip name-server route 8.8.4.4 5, configure DHCP pool conf tip dhcp pool testnetwork 192.168.20.0 255.255.255.0default-router 192.168.20.1dns-server 218.108.248.200 8.4.4 exitip dhcp excluded-address 192.168.20 192.168.20.100dhcp will not allocate addresses from 192.168.20.1 to 192.168.20.100. 6. Configure nat conf tinter fa0/0ip nat outside inter fa0/1ip nat inside exit www.2cto.com access-list 1 permit 192.168.20.0 0.0.255ip classlessip nat inside source list 1 interface fa0/0 overload 7. Configure the Router web conf tip http server (enabled by default) ip http port 8080 configures the user name and password used to access the web interface. You need to grant the level15 permission to this User username flw521521 privilege 15 password flw521521, the user name and password used to access the web interface are flw521521. 8. Configure the port ing conf t ip nat inside source static tcp 192.168.20.2 80 192.168.2.2 80 (ing the tcp port of 192.168.20.2 port tcp 80 of 192.168.2.2) ip nat inside source static udp 192.168.20.3 800 192.168.2.2 800 (ing the udp 800 port of 192.168.20.3 over the Intranet to the udp 800 port of 192.168.2.2) ip nat inside source static 192.168.20.2 192.168.2.3 (full port ing, make sure that 192.168.2.3 is not allocated in the Internet.) This is an external ing, and there is also an internal ing, which is generally not needed, for internal ing, as long as the Intranet host accesses the Intranet host, the Intranet ip address is not used, but the mapped Internet ip address is used, this requires that www.2cto.com 9 be mapped internally. Save the configuration write or copy running-config startup-config. If you need to clear all the configurations, run erase startup-configreload by flw521521.