Icmp Vulnerability; Illegal Commands (Netbios And Smtp); Figure 81 Smurf Attack; Table 57 Icmp Commands That Trigger Alerts - ZyXEL Communications P-661HW User Manual

P-661H/HW Series User's Guide

Figure 81 Smurf Attack

8.4.2.1 ICMP Vulnerability

ICMP is an error-reporting protocol that works in concert with IP. The following ICMP types
trigger an alert:

Table 57 ICMP Commands That Trigger Alerts

5
13
14
17
18

8.4.2.2 Illegal Commands (NetBIOS and SMTP)

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

Table 58 Legal NetBIOS Commands

MESSAGE:
REQUEST:
POSITIVE:
VE:
RETARGET:
KEEPALIVE:
All SMTP commands are illegal except for those displayed in the following tables.

Table 59 Legal SMTP Commands

AUTH DATA
QUIT RCPT
150
REDIRECT
TIMESTAMP_REQUEST
TIMESTAMP_REPLY
ADDRESS_MASK_REQUEST
ADDRESS_MASK_REPLY
EHLO ETRN EXPN
RSET SAML SEND
HELO HELP MAIL
SOML TURN VRFY
Chapter 8 Firewalls
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