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eircom D1000 modem U
ser’s Guide
Chapter 13 Firewall
13.1.2 What You Need to Know About Firewall
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 Device is pre-configured to automatically detect and thwart
all known DoS attacks.
DDoS
A Distributed DoS (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 Local Area Network Denial (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.
RFC 4890 SPEC Traffic
RFC 4890 specifies the filtering policies for ICMPv6 messages. This is important for protecting
against security threats including DoS, probing, redirection attacks and renumbering attacks that
can be carried out through ICMPv6. Since ICMPv6 error messages are critical for establishing and
maintaining communications, filtering policy focuses on ICMPv6 informational messages.
Summary of Contents for eircom D1000
Page 2: ...Copyright 2013 ZyXEL Communications Corporation...
Page 3: ......
Page 12: ...10 eircom D1000 modem User s Guide...
Page 13: ...PART I User s Guide 11...
Page 14: ...12...
Page 18: ...16 eircom D1000 modem User s Guide...
Page 26: ...Chapter 2 Introducing the Web Configurator 24 eircom D1000 modem User s Guide...
Page 27: ...PART II Technical Reference 25...
Page 28: ...26...
Page 78: ...76 eircom D1000 modem User s Guide Chapter 5 Wireless LAN...
Page 110: ...10 8 eircom D1000 modem User s Guide Chapter 6 Home Networking...
Page 126: ...Chapter 8 Quality of Service QoS 124 eircom D1000 modem User s Guide...
Page 136: ...134 eircom D1000 modem User s Guide Chapter 9 Network Address Translation NAT...
Page 148: ...146 eircom D1000 modem User s Guide Chapter 12 Filter...
Page 168: ...Chapter 14 Parental Control 166 eircom D1000 modem User s Guide...
Page 174: ...Chapter 15 Certificates 172 eircom D1000 modem User s Guide...
Page 180: ...178 eircom D1000 modem User s Guide Chapter 17 Traffic Status...
Page 182: ...180 eircom D1000 modem User s Guide Chapter 18 User Account...
Page 184: ...182 eircom D1000 modem User s Guide Chapter 19 System Setting...
Page 187: ...185 eircom D1000 modem User s Guide Chapter 20 Time Setting...
Page 188: ...Chapter 20 Time Setting 186 eircom D1000 modem User s Guide...
Page 196: ...Chapter 23 Backup Restore 194 eircom D1000 modem User s Guide...
Page 210: ...Chapter 25 Diagnostic 208 eircom D1000 modem User s Guide...
Page 216: ...214 eircom D1000 modem User s Guide Chapter 27 LED Descriptions...