A network technician is using telnet to connect to a router on a network that has been compromised. A new user and password has been added to the router with full rights. The technician is concerned that the regularly used administrator account has been compromised. After changing the password on all networking devices, which of the following should the technician perform to prevent the password for the administrator account from being sniffed on the network?
A. Use SNMPv1 for all configurations involving the router
B. Ensure the password is 10 characters, containing letter and numbers
C. Copy all configurations to routers using TFTP for secuirty
D. Only allow administrators to access routers using port 22