User Guide

20 Chapter 1. Advanced Topics
System Files
The router’s file system is a DOS-compatible file system, whose contents are as follows: :
SYSTEM.CNF:
These are configuration files containing:
DOD Remote Router Database
SYS System Settings: name, message, authentication method, and passwords
ETH Ethernet LAN configuration settings
DHCP.DAT:
DHCP files.
FILTER.DAT:
Bridge filters.
KERNEL.F2K:
Router system software (KERNEL.FP1 for IDSL routers).
ETH.DEF:
File used by the manufacturer to set a default Ethernet configuration.
ASIC.AIC:
Firmware for the xDSL modem or ATM interface.
ATM.DAT:
ATM configuration file.
I2TP Tunnening Database
ATOM.DAT
SDSL.DAT
DMT.DAT
IPSEC.DAT
IKE.DAT
AUTOEXEC.BAT - Autoexec file of commands to run on next reboot.
AUTOEXEC.OLD - Autoexec file that has run already
Note:
Users should not delete any of these files, unless advised by Tech Support.
Any file contained within the system may be retrieved or replaced using the TFTP protocol. Specifically,
configuration files and the operating system upgrades can be updated. Only one copy for the router software is
allowed in the router’s FLASH memory.
Refer to
Chapter 6. Managing the Router on page 215
for details on software upgrades, booting router software,
copying configuration files, and restoring router software to FLASH memory.
Bridge Filtering
You can control the flow of packets across the router using bridge filtering. Bridge filtering lets you “deny”or
“allow” packets to cross the network based on position and hexadecimal content within the packet. This feature
lets you restrict or forward messages with a specified address, protocol, or data content. Common uses are to
prevent access to remote networks, control unauthorized access to the local network, and limit unnecessary traffic.