D-Link DES-3528 - xStack Switch - Stackable Reference Manual page 352

xStack® DES-3528/DES-3552 Series Layer 2 Stackable Fast Ethernet Managed Switch Web UI Reference Guide
2. The switch will deny all other ARP packets which claim they are from the gateway's IP.
The design of Packet Content ACL on the Switch enables users to inspect any offset chunk. An offset chunk is a 4-byte
block in a HEX format, which is utilized to match the individual field in an Ethernet frame. Each profile is allowed to
contain up to a maximum of four offset chunks. Furthermore, only one single profile of Packet Content ACL can be
supported per switch. In other words, up to 16 bytes of total offset chunks can be applied to each profile and a switch.
Therefore, a careful consideration is needed for planning and configuration of the valuable offset chunks.
In Table 6, you will notice that the Offset_Chunk0 starts from the 127th byte and ends at the 128th byte. It also can be
found that the offset chunk is scratched from 1 but not zero.
Offset Offset Offset Offset
Chunk Chunk0 Chunk1 Chunk2
127 3 7
Byte
Byte
128 4 8
Byte
1 5 9
Byte
2 6 10
Offset Offset Offset Offset
Chunk Chunk16 Chunk17 Chunk18
Byte
63 67 71
Byte
64 68 72
Byte
65 69 73
Byte
66 70 74
The following table indicates a completed ARP packet contained in Ethernet frame which is the pattern for the
calculation of packet offset.
Command
create access_profile profile_id 1
Step 1:
profile_name 1 ethernet source_mac
FF-FF-FF-FF-FF-FF ethernet_type
config access_profile profile_id 1
Step 2:
add access_id 1 ethernet source_mac
01-02-03-04-05-06 ethernet_type
Offset Offset Offset Offset
Chunk3 Chunk4 Chunk5 Chunk6
11 15 19
12 16 20
13 17 21
14 18 22
Offset Offset Offset
Chunk19 Chunk20 Chunk21
75 79 83
76 80 84
77 81 85
78 82 86
Table 6. Chunk and Packet Offset
Table 5 A Completed ARP Packet Contained in an Ethernet Frame
Offset Offset Offset
Chunk7 Chunk8 Chunk9
23 27 31 35
24 28 32 36
25 29 33 37
26 30 34 38
Offset Offset Offset Offset
Chunk22 Chunk23 Chunk24 Chunk25
87 91 95 99
88 92 96 100
89 93 97 101
90 94 98 102
Description
Create access profile 1 to match Ethernet Type and
Source MAC address.
Configure access profile 1
Only if the gateway's ARP packet that contains the
343
Offset Offset Offset
Chunk10 Chunk11 Chunk12 Chunk13
39 43 47
40 44 48
41 45 49
42 46 50
Offset Offset Offset
Chunk26 Chunk27 Chunk28
103 107 111
104 108 112
105 109 113
106 110 114
Offset Offset Offset
Chunk14 Chunk15
51 55 59
52 56 60
53 57 61
54 58 62
Offset Offset Offset
Chunk29 Chunk30 Chunk31
115 119 123
116 120 124
117 121 125
118 122 126