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GL-6
Cisco Router and Security Device Manager 2.5 User’s Guide
OL-4015-12
CET
Cisco Encryption Technology. Proprietary network layer encryption introduced
in Cisco IOS Release 11.2. CET provides network data encryption at the IP
packet level and implements the following standards: DH, DSS, and 40- and
56-bit DES.
CHAP
Challenge Handshake Authentication Protocol. Security feature supported on
lines using PPP encapsulation that prevents unauthorized access. CHAP does not
itself prevent unauthorized access, it merely identifies the remote end. The
router or access server then determines whether that user is allowed access. See
also PAP.
chargen
Character Generation. Via TCP, a service that sends a continual stream of
characters until stopped by the client. Via UDP, the server sends a random
number of characters each time the client sends a datagram.
checksum
Computational method for checking the integrity of transmitted data, computed
from a sequence of octets taken through a series of arithmetic operations. The
recipient recomputes the value and compares it for verification.
Cisco SDM
Cisco Router and Security Device Manager. Cisco SDM is an Internet
browser-based software tool designed to configure LAN, WAN, and security
features on a router. See Getting Started for more information.
cipher
An encryption-decryption algorithm.
ciphertext
Encrypted, unreadable data, prior to its decryption.
CIR
Committed Information Rate. A configured long-term average committed rate to
enforce.
class map
Used by zone-based firewall policies to specify traffic that is to be handled
according to the actions specified in a policy map. A class map can specify a type
of traffic, and can also specify an ACL to define the source and destinaton of the
traffic.
clear channel
A clear channel is one through which non-encrypted traffic can flow. Clear
channels place no security restrictions on transmitted data.
cleartext
Decrypted text. Also called plaintext.