ZyXEL Communications UAG4100 User Manual page 151

PPPoE/PPTP Overview
Point-to-Point Protocol over Ethernet (PPPoE, RFC 2516) and Point-to-Point Tunneling Protocol
(PPTP, RFC 2637) are usually used to connect two computers over phone lines or broadband
connections. PPPoE is often used with cable modems and DSL connections. It provides the following
advantages:
• The access and authentication method works with existing systems, including RADIUS.
• You can access one of several network services. This makes it easier for the service provider to
offer the service
• PPPoE does not usually require any special configuration of the modem.
PPTP is used to set up virtual private networks (VPN) in unsecure TCP/IP environments. It sets up
two sessions.
The first one runs on TCP port 1723. It is used to start and manage the second one.
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The second one uses Generic Routing Encapsulation (GRE, RFC 2890) to transfer information
2
between the computers.
PPTP is convenient and easy-to-use, but you have to make sure that firewalls support both PPTP
sessions.
Chapter 10 Interfaces
UAG4100 User's Guide
151