Glossary
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Cisco Router and Security Device Manager Version 2.2 User’s Guide
OL-4015-08
spoofing
spoof
The act of a packet illegally claiming to be from an address from which it was
not actually sent. Spoofing is designed to foil network security mechanis ms such
as filters and access lists.
SRB source-route bridging. Method of bridging originated by IBM and popular in
Token Ring networks. In an SRB network, the entire route to a destination is
predetermined, in real time, prior to the sending of data to the destination.
SSH Secure Shell. An application running on top of a reliable transport layer, such as
TCP/IP, that provides strong authentication and encryption capabilities. Up to
five SSH clients are allowed simultaneous access to the router console.
SSL Secure Socket Layer. Encryption technology for the Web used to provide secure
transactions, such as the transmission of credit card numbers for e-commerce.
standard rule In SDM, a type of access rule or NAT rule. Standard rules compare a packet’s
source IP address against its IP address criteria to determine a match.Standard
rules use a wildcard mask to determine which portions of the IP address must
match.
state, stateful,
stateful Inspection
Network protocols maintain certain data, called state information, at each end of
a network connection between two hosts. State information is necessary to
implement the features of a protocol, such as guaranteed packet delivery, data
sequencing, flow control, and transaction or session IDs. Some of the protocol
state information is sent in each packet while each protocol is being used. For
example, a web browser connected to a web server uses HTTP and supporting
TCP/IP protocols. Each protocol layer maintains state information in the packets
it sends and receives. Routers inspect the state information in each packet to
verify that it is current and valid for every protocol it contains. This is called
stateful inspection and is designed to create a powerful barrier to certain types
of computer security threats
Static PAT Static Port Address Translation. A static address maps a local IP address to a
global IP address. Static PAT is a static address that also maps a local port to a
global port. See also PAT.
static route Route that is explicitly configured and entered into the routing table. Static
routes take precedence over routes chosen by dynamic routing protoc ols.