Cisco® ISP Essentials

Appendix F. Example ISP Access Security Migration Plan

This appendix gives one example of how an ISP could migrate its network equipment (routers, switches, and NAS) from a state in which Telnet access is open to the outside world to the point at which only specific authorized workstations are allowed access to the Telnet prompt.

Unfortunately, at the time this text was written, most ISPs were not taking these simple precautions to help secure their networks. This section is designed to help those ISPs put in the minimum necessary precautions. This is a simple procedure that draws a security circle around an ISP’s network and then slowly narrows the circle until just the authorized IP addresses are included in the VTY’s ACL.

Use this appendix in ...