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P-661H/HW Series User’s Guide
Chapter 9 Firewall Configuration
175
The following table describes the labels in this screen.
9.11 DoS Thresholds
For DoS attacks, the ZyXEL Device 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.
9.11.1 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 most small offices. Factors influencing
choices for threshold values are:
• The maximum number of opened sessions.
• The minimum capacity of server backlog in your LAN network.
• The CPU power of servers in your LAN network.
• Network bandwidth.
• Type of traffic for certain servers.
Table 66
Firewall: Anti Probing
LABEL
DESCRIPTION
Respond to PING
on
The ZyXEL Device does not respond to any incoming Ping requests when
Disable
is selected.
Select
LAN
to reply to incoming LAN Ping requests.
Select
WAN
to reply to incoming WAN Ping requests.
Otherwise select
LAN & WAN
to reply to both incoming LAN and WAN Ping
requests.
Do Not Respond to
Requests for
Unauthorized
Services.
Select this option to prevent hackers from finding the ZyXEL Device by probing for
unused ports. If you select this option, the ZyXEL Device will not respond to port
request(s) for unused ports, thus leaving the unused ports and the ZyXEL Device
unseen. By default this option is not selected and the ZyXEL Device will reply with
an ICMP Port Unreachable packet for a port probe on its unused UDP ports, and a
TCP Reset packet for a port probe on its unused TCP ports.
Note that the probing packets must first traverse the ZyXEL Device's firewall
mechanism before reaching this anti-probing mechanism. Therefore if the firewall
mechanism blocks a probing packet, the ZyXEL Device reacts based on the
corresponding firewall policy to send a TCP reset packet for a blocked TCP packet
or an ICMP port-unreachable packet for a blocked UDP packets or just drop the
packets without sending a response packet.
Apply
Click
Apply
to save your changes back to the ZyXEL Device.
Cancel
Click
Cancel
to begin configuring this screen afresh.
Содержание P-661H Series
Страница 2: ......
Страница 5: ...P 661H HW Series User s Guide Certifications 5...
Страница 10: ...P 661H HW Series User s Guide 10 Customer Support...
Страница 43: ...P 661H HW Series User s Guide Chapter 1 Getting To Know Your ZyXEL Device 43 Figure 5 Connecting a Microfilter...
Страница 44: ...P 661H HW Series User s Guide 44 Chapter 1 Getting To Know Your ZyXEL Device...
Страница 76: ...P 661H HW Series User s Guide 76 Chapter 3 Wizards...
Страница 108: ...P 661H HW Series User s Guide 108 Chapter 5 LAN Setup...
Страница 132: ...P 661H HW Series User s Guide 132 Chapter 6 Wireless LAN...
Страница 191: ...P 661H HW Series User s Guide Chapter 10 Trend Micro Security Services 191 Figure 113 Security Setting ActiveX Controls...
Страница 192: ...P 661H HW Series User s Guide 192 Chapter 10 Trend Micro Security Services...
Страница 196: ...P 661H HW Series User s Guide 196 Chapter 11 Content Filtering...
Страница 202: ...P 661H HW Series User s Guide 202 Chapter 12 Introduction to IPSec...
Страница 230: ...P 661H HW Series User s Guide 230 Chapter 13 VPN Screens...
Страница 234: ...P 661H HW Series User s Guide 234 Chapter 14 Static Route...
Страница 246: ...P 661H HW Series User s Guide 246 Chapter 15 Bandwidth Management...
Страница 250: ...P 661H HW Series User s Guide 250 Chapter 16 Dynamic DNS Setup...
Страница 280: ...P 661H HW Series User s Guide 280 Chapter 19 System...
Страница 290: ...P 661H HW Series User s Guide 290 Chapter 21 Tools...
Страница 296: ...P 661H HW Series User s Guide 296 Chapter 23 Troubleshooting...
Страница 300: ...P 661H HW Series User s Guide 300 Appendix A...
Страница 304: ...P 661H HW Series User s Guide 304 Appendix C...
Страница 326: ...P 661H HW Series User s Guide 326 Appendix E...
Страница 328: ...P 661H HW Series User s Guide 328 Appendix F...
Страница 334: ...P 661H HW Series User s Guide 334 Appendix G...
Страница 368: ...P 661H HW Series User s Guide 368 Appendix K...
Страница 376: ...P 661H HW Series User s Guide 376 Figure 219 Java Sun...