User's Manual

114
provide a sort of firewall and allow for a wider address range to be used internally
without danger of conflict. Using the router‟s NAT capability, you can access the
Internet from any computer on your home network without having to purchase
more IP addresses from your ISP.
Port
Network Clients (LAN PC) uses port numbers to distinguish one network
application/protocol over another. Below is a list of common applications and
protocol/port numbers:
Application
Protocol
Port Number
Telnet
TCP
23
FTP
TCP
21
SMTP
TCP
25
POP3
TCP
110
H.323
TCP
1720
SNMP
UCP
161
SNMP Trap
UDP
162
HTTP
TCP
80
PPTP
TCP
1723
PC Anywhere
TCP
5631
PC Anywhere
UDP
5632
PPP
PPP is the Point-to-Point-Protocol. The successor to SLIP, PPP provides router-
to-router and host-to-network connections over both synchronous and
asynchronous circuits.
PPPoA (RFC 2364)
The Point-to-Point Protocol (PPP) provides a standard method for transporting
multi-protocol data grams over point-to-point links. This document describes the
use of ATM Adaptation Layer 5 (AAL5) for framing PPP encapsulated packets.