Figure 84 Smurf Attack; Table 53 Icmp Commands That Trigger Alerts; Table 54 Legal Netbios Commands; Table 55 Legal Smtp Commands - ZyXEL Communications P-660H Series User Manual

P-660H/HW-D Series User's Guide

Figure 84 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:

Table 53 ICMP Commands That Trigger Alerts

5
13
14
17
18

9.4.2.2 Illegal Commands (NetBIOS and SMTP)

The only legal NetBIOS commands are the following - all others are illegal.

Table 54 Legal NetBIOS Commands

MESSAGE:
REQUEST:
POSITIVE:
VE:
RETARGET:
KEEPALIVE:
All SMTP commands are illegal except for those displayed in the following tables.
Table 55
AUTH DATA
QUIT RCPT
149
REDIRECT
TIMESTAMP_REQUEST
TIMESTAMP_REPLY
ADDRESS_MASK_REQUEST
ADDRESS_MASK_REPLY
Legal SMTP Commands
EHLO ETRN
RSET SAML
EXPN HELO HELP
SEND SOML TURN
MAIL NOOP
VRFY
Chapter 9 Firewalls