How to Work with ADSL Modem?

Basic Concept of ADSL
ADSL is a common technology for Internet access. Basic function of an ADSL modem is to provide Ethernet connectivity over telephone wire so that a PC at customer site and the system at service provider site can exchange data. In order to validate the user, a protocol, such as PPPoE (sometime using PPPoA or PPTP), is used for authentication. The PPPoE client software is running on a PC or an access router at the customer site. PPPoE account name and password are obtained from the service provider. Once authentication is completed, the local network at the customer site will be granted with a public IP address.
Nowadays, ADSL modem and a small access router are built into one device. Such integrated access device (ADSL router) provides multiple functions:

ADSL modem that allows data frames to be carried over telephone wire;
Access router that performs PPPoE or PPPoA function, IP routing function, DHCP service, network address translation, and maybe simple firewall function.
LAN switch that has multiple Ethernet ports allowing multiple PC behind the router to share the Internet access.

IPX on Public Internet
Ideally, the IPX should be used as access router. In order words, an ADSL modem only provides a simple and dummy modem function - Ethernet Bridge. The IPX, running PPPoE, obtains a public IP address and provides NAT/Firewall functions. The IPX will have better QoS control on data traffic and ensure voice communication to have better quality.

Turn the Integrated Device back to a Simple ADSL modem
If you are using an ADSL router and you like the IPX to have public IP address used as access router, you will need to change the ADSL router to a simple modem by disabling its router capability. Here are a few steps:

Write down PPPoE account name and password and keep it in safe place. If it is lost, you can ask your ISP.
Connect a PC to the ADSL device. From a Windows CMD window, command "ipconfig" displays default gateway/default router's IP address, e.g. User can launch Internet Explorer with the address, e.g. User manual of the ADSL router should have the default login name and password.
Go to the advanced configuration sections, search for virtual connection (VCI and VPI) configuration, and change the protocol PPPoE to bridge protocol on the connection channel. Any changes made in the ADSL router must be saved.
Configure the PPPoE account on the IPX WAN interface.

Place the IPX in Private LAN
If the ADSL router uses PPPoA or PPTP for the Internet access, you will have to place the IPX behind the ADSL router. Most people do not want change the existing network. In this case, you can also put the IPX behind the ADSL router. You will need to configure DMZ or port forwarding on the ADSL router. Other IPX uses the domain name of this IPX to reach the IPX. Refer to "How to Work with Firewall" for related information.


Orionox Live Help