Glossary
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Cisco Router and Security Device Manager 2.5 User’s Guide
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standard rule In Cisco 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.
subnet, subnetwork In IP networks, a network sharing a particular subnet address. Subnetworks are
networks arbitrarily segmented by the network administrator in order to provide
a multilevel, hierarchical routing structure while shielding the subnetwork from
the addressing complexity of attached networks. See also IP address, subnet bits,
subnet mask.
subnet bits
subnet mask
32-bit address mask used in IP to indicate the bits of an IP address that are being
used for the network and optional subnet address. Subnet masks are expressed
in decimal. The mask 255.255.255.0 specifies that the first 24 bits of the address
Sometimes referred to simply as mask. See also address mask and IP address.
SUNRPC SUN Remote Procedure Call. RPC is a protocol that allows clients to run
programs or routines on remote servers. SUNRPC is the version of RPC
originally distributed in the SUN Open Network Computing (ONC) library.
symmetric key A symmetric key is used to decrypt information that it previously encrypted.