Auerswald COMpact 4000 Operation Manual page 769

Glossary
Terminology
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PTP Connection
This is an ISDN connection with Direct Dial In option. A provider allocates a PBX base number
with additional Direct Dial In numbers (DDIs), e.g., 9200–0. PBXs are usually operated on a
PTP connection.
Port
A single PC can simultaneously establish multiple connections and provide multiple services
for other PCs. Ports are used to differentiate these connections from parallel connections. Due
to a common agreement, PCs usually provide their services on ports 1 to 1023. Outgoing
connections are usually established starting at Port 1024. Most services that use the standard
port numbers (for example, web browsers use port 80).
Proxy
A proxy server acts as the interface to the Internet or between two networks. For example, it
receives queries from a computer in an intranet. It then connects to the Internet (on behalf of
the computer) to forward the queries and return the (if necessary, filtered) responses. To
achieve this, the HTTP proxy uses the Internet's HTTP protocol.
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Router
Routers connect two separate networks. This means, for example, that you can connect the
local network to another LAN or a WAN. When a PC wants to send a data packet, this packet
must travel over a router. The router uses the IP address to detect the network it must send the
data to. In addition to connecting to networks, routers can also execute certain control
functions, such as maintaining a simple firewall. In a home network, routers are usually used
to connect the local network to the Internet and to enable simultaneous Internet access for
multiple users.
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COMpact 4000 - Firmware V6.6A - Installation, Operation and Configuration V03 03/2016