System information

xStack
®
DGS-3200 Series Layer 2 Gigabit Ethernet Managed Switch
155
Packet Content
Allows users to examine up to four specified offset chunks within a packet, one at a time. A
chunk mask presents four bytes. Four offset chunks can be selected from a possible 32
predefined offset chunks as described below:
offset_chunk_1,
offset_chunk_2,
offset_chunk_3,
offset_chunk_4.
chunk0 chunk1 chunk2 …… chunk29 chunk30 chunk31
B126,
B127,
B0,
B1
B2,
B3,
B4,
B5
B6,
B7,
B8,
B9
…… B114,
B115,
B116,
B117
B118,
B119,
B120,
B121
B122,
B123,
B124,
B125
Example:
offset_chunk_1 0 0xffffffff will match packet byte offset 126, 127, 0, 1
offset_chunk_1 0 0x0000ffff will match packet byte offset, 0,1
Note:
Only one packet content mask profile can be created at a time. Use of the D-Link xStack
switch family’s advanced Packet Content Mask (also known as Packet Content Access
Control List – ACL) feature can effectively mitigate common network attacks such as ARP
Spoofing. The Switch’s implementation of Packet Content ACL enables inspection of any
packet’s specified content regardless of the protocol layer.
Click Apply to implement changes made.
To view the setting details for a created profile, click the Show Details button for the corresponding entry on the Access Profile
List window, revealing the following window:
Figure 6 - 9. Access Profile Detail Information window for Packet Content
NOTE: Address Resolution Protocol (ARP) is the standard for finding a host’s hardware
address (MAC address). However, ARP is vulnerable as it can be easily spoofed and utilized
to attack a LAN (i.e. an ARP spoofing attack). For a more detailed explanation on how ARP
protocol works and how to employ D-Link’s unique Packet Content ACL to prevent ARP
spoofing attack, please see Appendix E at the end of this manual.
To establish the rule for a previously created Access Profile:
To configure the Access Rules for Ethernet, open the Access Profile List window and click Add/View Rules for an Ethernet
entry. This will open the following window: