ZyXEL Communications ZyXEL ZyWALL 5 - Manual (Page 159)

ZyWALL 5 User’s Guide
158 Chapter 9 Firewalls
Figure 61 Smurf Attack
9.4.2.1 ICMP Vulnerability
ICMP is an error-reporting protocol that works in concert with IP. The following ICMP types
trigger an alert:
9.4.2.2 Illegal Commands (NetBIOS and SMTP)
The only legal NetBIOS commands are the following - all others are illegal.
Table 45 ICMP Commands That Trigger Alerts
5 REDIRECT
13 TIMESTAMP_REQUEST
14 TIMESTAMP_REPLY
17 ADDRESS_MASK_REQUEST
18 ADDRESS_MASK_REPLY
Table 46 Legal NetBIOS Commands
MESSAGE:
REQUEST:
POSITIVE:
NEGATIVE:
RETARGET:
KEEPALIVE: