Prestige 652H/HW Series User’s Guide
12-4
Firewalls
21 FTP
53 DNS
23 Telnet
80 HTTP
25 SMTP
110
POP3
12.4.2 Types of DoS Attacks
There are four types of DoS attacks:
1. Those that exploit bugs in a TCP/IP implementation.
2. Those that exploit weaknesses in the TCP/IP specification.
3. Brute-force attacks that flood a network with useless data.
4. IP
Spoofing.
1. "
Ping of Death
" and "
Teardrop
" attacks exploit bugs in the TCP/IP implementations of various
computer and host systems.
1-a Ping of Death uses a "ping" utility to create an IP packet that exceeds the maximum 65,536
bytes of data allowed by the IP specification. The oversize packet is then sent to an unsuspecting
system. Systems may crash, hang or reboot.
1-b Teardrop attack exploits weaknesses in the re-assembly of IP packet fragments. As data is
transmitted through a network, IP packets are often broken up into smaller chunks. Each fragment
looks like the original IP packet except that it contains an offset field that says, for instance, "This
fragment is carrying bytes 200 through 400 of the original (non fragmented) IP packet." The
Teardrop program creates a series of IP fragments with overlapping offset fields. When these
fragments are reassembled at the destination, some systems will crash, hang, or reboot.
2. Weaknesses in the TCP/IP specification leave it open to "
SYN Flood
" and "
LAND
" attacks. These
attacks are executed during the handshake that initiates a communication session between two
applications.
Summary of Contents for Prestige 652H series
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Page 120: ...Prestige 652H HW Series User s Guide 8 12 WAN Setup Figure 8 6 Advanced WAN Backup ...
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Page 178: ...Prestige 652H HW Series User s Guide 13 16 Firewall Screens Figure 13 8 Rule Edit Example ...
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Page 214: ...Prestige 652H HW Series User s Guide 16 10 VPN Screens Figure 16 5 VPN IKE ...
Page 227: ...Prestige 652H HW Series User s Guide VPN Screens 16 23 Figure 16 8 Manual Setup ...
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Page 277: ...Maintenance VIII Part VIII Maintenance This part covers the maintenance screens ...
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