Configuring the Router via TFTP

Generally, most people configure their routers using Telnet and the configure terminal command. For large configuration changes, people tend to resort to cutting and pasting a large set of commands. While this method works, it is inefficient and slow, particularly if you have to configure large numbers of routers. When you use TFTP to download a large set of configuration commands, the router doesn't need to echo each character to your screen, which reduces the overhead and increases the speed.

You can use the copy t ftp: command to configure the router via the TFTP:

Router1#copy tftp://172.25.1.1/EBRAHMACONFIG running-config
Destination filename [running-config]? <enter>
Accessing tftp://172.25.1.1/NEWCONFIG...
Loading EBRAHMACONFIG from 172.25.1.1 (via FastEthernet0/0.1): !
[OK - 24 bytes]
  
24 bytes copied in 0.192 secs (125 bytes/sec)

In our example, we configured the router by making it download the file called EBRAHMACONFIG from the server at 172.25.1.1 using TFTP. The router copies the entire file via TFTP before entering the commands into the running configuration. This is extremely useful because using some commands in the middle of a configuration could disrupt your access to the router—but the rest of the commands might fix the problem. If you tried to enter them manually using Telnet and configure terminal, you would simply lock yourself out of the router. A typical example of this problem happens when you replace an active access list. When you enter the first line, the router puts an implicit deny all at the end, which could break your session. 

However, entering commands using TFTP avoids this problem.