Lightning SA MultiCom, Руководство пользователя

Страница: 108 / 172

Chapter 6 Frequently Asked Questions
108 MultiCom Firewall User’s Manual
My changed configuration disappeared after a reboot, what happened?
If you only save a configuration to the Current Config memory location in
your firewall it is only temporary and will be erased after a reboot. This is
useful for tests and quick changes. Be sure to always backup your config
changes to a text file and/or keep a copy in one of the permanent memory
locations in the firewall.
After making changes to the configuration I cannot reach the firewall any more.
Since you communicate with the firewall via an Ethernet connection it is
possible to accidentally filter all traffic or route it incorrectly and hence block
your own access to the firewall. In that case you will need to reboot the
firewall into the default configuration and either edit your saved configuration
or make a new one.
What is the default configuration of the firewall?
The while the default setting may be changed by your distributor or Internet
To see the default configuration installed in the Ethernet firewall see the
Concepts Chapter of the Lightning-Linux Reference Manual.
Why do some network services seem very slow after I have applied filtering?
Be sure to have read the chapter on filtering data and that you understand how
your software communicates with remote servers. In particular port 113 is
often used to verify if a communication link is valid and if all external packets
are being dropped instead of rejected (allowing a message to be sent back to
the remote server) the software keeps waiting for a response, eventually
timing out.
How do I know what ports are being used?
The best place is to check with the manufacturer of the software that you are
using. Consider using network monitoring software such as network monitor
for Windows NT Server or the free software Ethereal at
http://www.ethereal.com/ to track usage over a general amount of time and
identify ports and addresses that are commonly being used.
Another option is to set the filters on your Ethernet firewall to log all types of
TCP and/or UDP data. Your Syslog server will receive messages reporting all
network traffic and you can then study the output for common usage types.
Can I use the firewall as a bridge?
The Ethernet firewall is not designed to be used as a bridge at this time.