O'Reilly logo

CCIE Security Exam Certification Guide by Henry Benjamin

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Secure Shell

Secure Shell (SSH) is a protocol that provides a secure connection to a router. Cisco IOS supports version 1 of SSH, which enables clients to make a secure and encrypted connection to a Cisco router. Before SSH was implemented, the only form of security available when accessing devices such as routers was Telnet username/password authentication, which is clearly visible with a network sniffer. Telnet is insecure because a protocol analyzer can view the information in clear text form. Figure 3-8 displays a simple protocol analyzer viewing information between a source address, 10.66.32.5, and the destination address 192.168.1.13 after a Telnet session is initiated by the address (PC) 192.168.1.13/24.

Figure 3-8. Sniffer Capture of ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required