Adsl Routers

ADSL routers, ADSL modem also called, are electronic devices that can connect a LAN to the Internet via a fixed telephone line ADSL. Basically ADSL routers are devices that meet five functions on a single computer: gateway (Internet provides output to the LAN with a single external IP), router (routes data packets), ADSL modem (modulator / demodulator ADSL), switch LAN (Ethernet) and WLAN access point (Wi-Fi).

Features

ADSL Routers provide Internet access to a LAN (Local Area Network, Local Area Network) via a fixed telephone line that has ADSL enabled. Although called routers, that's just one of the functions performed by the ADSL routers:

Gateway (gateway or gateway) provides output to the external network to local network machines, made to do NAT and IP Masquerading operations, providing Internet access to local network computers sharing a single Internet connection with a single external IP. Router (router): performs the interconnection of computer networks by routing data packets. ADSL Modem: it acts as a modulator of the signals sent from the LAN to the ADSL line, and a demodulator to interpret the signals coming from the outside. Switch: Create a wired Ethernet LAN. Wireless access point, allows to create a WLAN (Wireless LAN, Wireless Local Area Network) via Wi-Fi. Additional features: often have advanced features such as DHCP server, DNS server, packet filtering, encryption or firewall.

Connections

ADSL routers have to connect both to the Internet via ADSL line to the local network. To do this use the following links:

Externally: To connect to the landline has a RJ-11 interface. Inland: for wired Ethernet LAN, ADSL routers have one or more RJ-45, while for the WLAN interface have Wi-Fi. Configuration

ADSL routers tend to have multiple configuration systems:

Web interface, including a password protected web server to configure the device. Remote Shell: usually have a Telnet or SSH server that opens a remote shell. Local Shell: through serial port and local shell. Open ports

Generally ADSL routers are factory set to reject requests to certain ports, and only bring open ports configuration and 22/tcp (SSH) 23/tcp (Telnet) and 80/TCP (HTTP).

This makes ADSL routers have limited the ability to access services such as P2P, online gaming, video conferencing or VoIP calls, so if we use these applications or servers, will be opened on the router's ports.

Microfilters

To use telephone equipment such as telephones, analog modems, or fax in an ADSL line, install microfilters to reduce interference, one on each telephone equipment up to three.

Source: ADSL Routers