ZyXEL Communications 50 User Manual
ZyWALL 50 Internet Security Gateway
Using the ZyWALL Web Configurator
9-7
Figure 9-4 E-mail Log
9.4 Attack
Alert
Attack alerts are the first defense against DOS attacks. In the Attack Alert screen, shown later, you may
choose to generate an alert whenever an attack is detected. For DoS attacks, the ZyWALL uses thresholds to
determine when to drop sessions that do not become fully established. These thresholds apply globally to all
sessions.
choose to generate an alert whenever an attack is detected. For DoS attacks, the ZyWALL uses thresholds to
determine when to drop sessions that do not become fully established. These thresholds apply globally to all
sessions.
You can use the default threshold values, or you can change them to values more suitable to your security
requirements.
requirements.
9.4.1 Threshold Values
Tune these parameters when something is not working and after you have checked the firewall counters.
These default values should work fine for normal small offices with ADSL bandwidth. Factors influencing
choices for threshold values are:
These default values should work fine for normal small offices with ADSL bandwidth. Factors influencing
choices for threshold values are:
1. The maximum number of opened sessions.
Subject:
Firewall Alert From ZyWALL
Date:
Fri, 07 Apr 2000 10:05:42
From:
user@zyxel.com
To:
user@zyxel.com
1|Apr
7 00 |From:192.168.1.1
To:192.168.1.255
|default policy
|forward
| 09:54:03 |UDP
src port:00520 dest port:00520
|<1,00>
|
2|Apr
7 00 |From:192.168.1.131
To:192.168.1.255
|default policy
|forward
| 09:54:17 |UDP
src port:00520 dest port:00520
|<1,00>
|
3|Apr
7 00 |From:192.168.1.6
To:10.10.10.10 |match
|forward
| 09:54:19 |UDP
src port:03516 dest port:00053
|<1,01>
|
……………………………..{snip}…………………………………..
……………………………..{snip}…………………………………..
126|Apr
……………………………..{snip}…………………………………..
126|Apr
7 00 |From:192.168.1.1
To:192.168.1.255
|match
|forward
| 10:05:00 |UDP
src port:00520 dest port:00520
|<1,02>
|
127|Apr
7 00 |From:192.168.1.131
To:192.168.1.255
|match
|forward
| 10:05:17 |UDP
src port:00520 dest port:00520
|<1,02>
|
128|Apr
7 00 |From:192.168.1.1
To:192.168.1.255
|match
|forward
| 10:05:30 |UDP
src port:00520 dest port:00520
|<1,02>
|
End of Firewall Log
The date format here
is Day-Month-Year.
is Day-Month-Year.
The date format here
is Month-Day-Year.
The time format is
Hour-Minute-Second.
is Month-Day-Year.
The time format is
Hour-Minute-Second.
"End of Log" message
shows that a complete
log has been sent.
shows that a complete
log has been sent.
You may edit the
subject title
subject title