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authenticator, and the authenticator forwards the credentials to the authentication server for verification. If the
authentication server determines the credentials are valid, the supplicant (client device) is allowed to access
resources located on the protected side of the network.
Port Mirroring
Network Engineers or Administrators use port mirroring to copy traffic from multiple ports to the mirroring
destination port for analyzing and debugging data or diagnosing errors on a network. It helps the administrator keep
a close eye on network performance and will alert him when problems occur (Mirroring traffic here is equivalent to
copying traffic.). It can be used to mirror either inbound or outbound traffic on single or multiple interfaces.
LACP
Within the IEEE specification the Link Aggregation Control Protocol (LACP) provides a method to control the
bundling of several physical ports together to form a single logical channel. In this way, link bandwidth is increased,
available redundancy is raised and transmission quality is also enhanced.
ACL
An ACL (Access Control List) contains entries that specify individual user or group rights to specific system
objects such as programs or processes. These entries are known as access control entries (ACEs). Each accessible
object contains an identifier to its ACL. The privileges or permissions determine specific access rights. On some
types of proprietary computer hardware (in particular routers and switches), an Access Control List refers to rules
that are applied to port numbers or IP Addresses that are available on a host or other layer 3, each with a list of
hosts and/or networks permitted to use the service. Both individual servers as well as routers can have network
ACLs. Access control lists can generally be configured to control both inbound and outbound traffic, and in this
context they are similar to firewalls.
DHCP
The Dynamic Host Configuration Protocol (DHCP) is a network protocol that is used to configure network devices
so that they can communicate on an IP network. A DHCP client uses the DHCP protocol to acquire configuration
information, such as an IP address, a default route and one or more DNS server addresses from a DHCP server. The
DHCP client then uses this information to configure its host. Once the configuration process is complete, the host is
able to communicate on the Internet. The DHCP server maintains a database of available IP addresses and
configuration information, ensuring each IP address assigned is unique on the network. A valid IP address (lease
time has not expired) will never be allocated to a second client. The IP pool is maintained by the DHCP server
itself instead of a network administrator.
ARP
Address Resolution Protocol (ARP) is a protocol used for resolution of network layer addresses into link layer
addresses, such as Ethernet addresses. In order to communicate with a neighbor host, the host needs to first know
its neighbor's IP address. It also needs to know its neighbor's MAC address by sending a broadcast ARP message
requesting an answer for the neighbor's IP address.
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