D-Link DFL-80 User Manual - Page 128

IP Spoofing, Network Address Translation, Packet Filtering, Address

Get D-Link DFL-80 PDF manuals and user guides View all D-Link DFL-80 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 128 highlights

IP Spoofing Data packets sent is from a fake source address. If the firewall's policy does not restrict these packets from passing through, they could be used to attack internal servers easily. Network Address Translation NAT is the translation of IP addresses between internal or private networks and the public IP addresses on the Internet. There are three IP address blocks that have been assigned as private IP address space: 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 Through the NAT mechanism, an enterprise's internal networks can use any IP addresses that fall in the three private spaces. Note that, private IP addresses can not pass through routers to their destinations. Packet Filtering Packet Filters check the headers of IP, TCP and ICMP packets to gather information, such as sources addresses, source ports, destination addresses, and destination ports. It also checks the relationships between packets to decide whether a packet is for normal connection. In this way, attacks can be detected and blocked. Address Each address in Address Table can be either an IP address or a sub-network address. Administrators can create a name for a specific address for easier reference. Basically, base on the networks they are located, IP address falls into 3 categories: Internal IP addresses, external IP addresses and DMZ IP addresses. When setting up policies, administrators choose IP addresses in Address Table as the source/destination addresses. So Address Table has to be constructed before setting up policies. 128

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
128
IP Spoofing
Data packets sent is from a fake source address.
If the firewall’s policy does
not restrict these packets from passing through, they could be used to attack
internal servers easily.
Network Address Translation
NAT is the translation of IP addresses between internal or private networks and
the public IP addresses on the Internet.
There are three IP address blocks that
have been assigned as private IP address space:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
Through the NAT mechanism, an enterprise’s internal networks can use any IP
addresses that fall in the three private spaces. Note that, private IP addresses
can not pass through routers to their destinations.
Packet Filtering
Packet Filters check the headers of IP, TCP and ICMP packets to gather
information, such as sources addresses, source ports, destination
addresses, and destination ports.
It also checks the relationships between
packets to decide whether a packet is for normal connection. In this way,
attacks can be detected and blocked.
Address
Each address in Address Table can be either an IP address or a sub-network
address. Administrators can create a name for a specific address for easier
reference. Basically, base on the networks they are located, IP address falls
into 3 categories: Internal IP addresses, external IP addresses and DMZ IP
addresses.
When setting up policies, administrators choose IP addresses in
Address Table as the source/destination addresses. So Address Table has to
be constructed before setting up policies.