Glossary
GL-16
Cisco ASA 5500 Series Configuration Guide using ASDM
OL-20339-01
Proxy-ARP
Enables the adaptive security appliance to reply to an ARP request for IP addresses in the global pool. 
See also ARP.
public key
A public key is one of a pair of keys that are generated by devices involved in public key infrastructure. 
Data encrypted with a public key can only be decrypted using the associated private key. When a 
private key is used to produce a digital signature, the receiver can use the public key of the sender to 
verify that the message was signed by the sender. These characteristics of key pairs provide a scalable 
and secure method of authentication over an insecure media, such as the Internet.
Q
QoS
quality of service. Measure of performance for a transmission system that reflects its transmission 
quality and service availability.
R
RA
Registration Authority. An authorized proxy for a CA. RAs can perform certificate enrollment and can 
issue CRLs. See also CA, certificate, public key.
RADIUS
Remote Authentication Dial-In User Service. RADIUS is a distributed client/server system that 
secures networks against unauthorized access. RFC 2058 and RFC 2059 define the RADIUS protocol 
standard. See also AAA and TACACS+.
refresh
Retrieve the running configuration from the adaptive security appliance and update the screen. The 
icon and the button perform the same function.
registration 
authority
See RA.
replay-detection
A security service where the receiver can reject old or duplicate packets to defeat replay attacks. 
Replay attacks rely on the attacker sending out older or duplicate packets to the receiver and the 
receiver thinking that the bogus traffic is legitimate. Replay-detection is done by using sequence 
numbers combined with authentication and is a standard feature of IPsec.
RFC
Request for Comments. RFC documents define protocols and standards for communications over the 
Internet. RFCs are developed and published by IETF.
RIP
Routing Information Protocol. Interior Gateway Protocol (IGP) supplied with UNIX BSD systems. 
The most common IGP in the Internet. RIP uses hop count as a routing metric.
RLLA
Reserved Link Local Address. Multicast addresses range from 224.0.0.0 to 239.255.255.255; however 
only the range 224.0.1.0 to 239.255.255.255 is available to users. The first part of the multicast 
address range, 224.0.0.0 to 224.0.0.255, is reserved and referred to as the RLLA. These addresses are 
unavailable.
route, routing
The path through a network.
routed firewall 
mode
In routed firewall mode, the adaptive security appliance is counted as a router hop in the network. It 
performs NAT between connected networks and can use OSPF or RIP. See also transparent firewall 
mode.