Glossary
GL-22
Cisco Router and Security Device Manager Version 2.2 User’s Guide
OL-4015-08
P
PAD packet assembler/disassembler. Device used to connect simple devices (like
character-mode terminals) that do not support the full functionality of a
particular protocol to a network. PADs buffer data and assemble and disassemble
packets sent to such end devices.
padding In cryptosystems, padding refers to random characters, blanks, zeros, an d nulls
added to the beginning and ending of messages, to conceal their actual length o r
to satisfy the data block size requirements of some ciphers. Padding also
obscures the location at which cryptographic coding actually starts.
PAM Port to Application Mapping. PAM allows you to customize TCP or UDP port
numbers for network services or applications. PAM uses this information to
support network environments that run services using ports that are different
from the registered or well-known ports associated with an application.
PAP Password Authentication Protocol. An authentication protocol that allows peers
to authenticate one another. PAP passes the password and hostname or username
in unencrypted form. See also CHAP.
password A protected and secret character string (or other data source) associated with the
identity of a specific user or entity.
PAT
Dynamic PAT
Port Address Translation. Dynamic PAT lets multiple outbound sessions appear
to originate from a single IP address. With PAT enabled, the router chooses a
unique port number from the PAT IP address for each outbound translation slot
(xlate). This feature is valuable when an Internet service provider cannot
allocate enough unique IP addresses for your outbound connections. Th e global
pool addresses always come first, before a PAT address is used.
peer In IKE, peers are routers acting as proxies for the participants in an IKE tunnel.
In IPSec, peers are devices or entities that communicate securely either through
the exchange of keys or the exchange of digital certificates.
PFS perfect forward secrecy. A property of some asymmetric key agreement
protocols that allows for the use of different keys at different times d uring a
session, to ensure that the compromising of any single key will not compromise
the session as a whole.