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Chapter 17 Firewall
VMG5313-B10A/-B30A Series User’s Guide
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17.1.2 What You Need to Know
SYN Attack
A SYN attack floods a targeted system with a series of SYN packets. Each packet causes the
targeted system to issue a SYN-ACK response. While the targeted system waits for the ACK that
follows the SYN-ACK, it queues up all outstanding SYN-ACK responses on a backlog queue. SYN-
ACKs are moved off the queue only when an ACK comes back or when an internal timer terminates
the three-way handshake. Once the queue is full, the system will ignore all incoming SYN requests,
making the system unavailable for legitimate users.
DoS
Denials of Service (DoS) attacks are aimed at devices and networks with a connection to the
Internet. Their goal is not to steal information, but to disable a device or network so users no longer
have access to network resources. The ZyXEL Device is pre-configured to automatically detect and
thwart all known DoS attacks.
DDoS
A DDoS attack is one in which multiple compromised systems attack a single target, thereby
causing denial of service for users of the targeted system.
LAND Attack
In a LAND attack, hackers flood SYN packets into the network with a spoofed source IP address of
the target system. This makes it appear as if the host computer sent the packets to itself, making
the system unavailable while the target system tries to respond to itself.
Ping of Death
Ping of Death uses a "ping" utility to create and send an IP packet that exceeds the maximum
65,536 bytes of data allowed by the IP specification. This may cause systems to crash, hang or
reboot.
SPI
Stateful Packet Inspection (SPI) tracks each connection crossing the firewall and makes sure it is
valid. Filtering decisions are based not only on rules but also context. For example, traffic from the
WAN may only be allowed to cross the firewall in response to a request from the LAN.
Содержание VMG5313-B10A
Страница 15: ...15 PART I User s Guide ...
Страница 16: ...16 ...
Страница 32: ...Chapter 2 The Web Configurator VMG5313 B10A B30A Series User s Guide 32 ...
Страница 40: ...Chapter 4 Tutorials VMG5313 B10A B30A Series User s Guide 40 ...
Страница 71: ...71 PART II Technical Reference ...
Страница 72: ...72 ...
Страница 78: ...Chapter 5 Network Map and Status Screens VMG5313 B10A B30A Series User s Guide 78 ...
Страница 106: ...Chapter 6 Broadband VMG5313 B10A B30A Series User s Guide 106 ...
Страница 162: ...Chapter 9 Routing VMG5313 B10A B30A Series User s Guide 162 ...
Страница 180: ...Chapter 10 Quality of Service QoS VMG5313 B10A B30A Series User s Guide 180 ...
Страница 198: ...Chapter 11 Network Address Translation NAT VMG5313 B10A B30A Series User s Guide 198 ...
Страница 210: ...Chapter 14 Interface Group VMG5313 B10A B30A Series User s Guide 210 ...
Страница 218: ...Chapter 15 USB Service VMG5313 B10A B30A Series User s Guide 218 ...
Страница 232: ...Chapter 17 Firewall VMG5313 B10A B30A Series User s Guide 232 ...
Страница 240: ...Chapter 19 Parental Control VMG5313 B10A B30A Series User s Guide 240 ...
Страница 250: ...Chapter 21 Certificates VMG5313 B10A B30A Series User s Guide 250 ...
Страница 296: ...Chapter 23 Voice VMG5313 B10A B30A Series User s Guide 296 ...
Страница 300: ...Chapter 24 Log VMG5313 B10A B30A Series User s Guide 300 ...
Страница 308: ...Chapter 27 xDSL Statistics VMG5313 B10A B30A Series User s Guide 308 ...
Страница 318: ...Chapter 30 Remote Management VMG5313 B10A B30A Series User s Guide 318 ...
Страница 322: ...Chapter 32 TR 064 VMG5313 B10A B30A Series User s Guide 322 ...
Страница 332: ...Chapter 36 Log Setting VMG5313 B10A B30A Series User s Guide 332 ...
Страница 335: ...Chapter 37 Firmware Upgrade VMG5313 B10A B30A Series User s Guide 335 Figure 176 Error Message ...
Страница 336: ...Chapter 37 Firmware Upgrade VMG5313 B10A B30A Series User s Guide 336 ...
Страница 352: ...Chapter 40 Troubleshooting VMG5313 B10A B30A Series User s Guide 352 ...
Страница 353: ...353 PART III Appendices Appendices contain general information Some information may not apply to your device ...
Страница 354: ...354 ...
Страница 374: ...Appendix B Wireless LANs VMG5313 B10A B30A Series User s Guide 374 ...
Страница 390: ...Appendix E Legal Information VMG5313 B10A B30A Series User s Guide 390 ...