CHAPTER 5: Advanced Setup Menu
65
Advanced Filters are used to regulate traffic in both directions. (Refer to Figure 5-36).
• From LAN to the Link. Using filters here will forward or block traffic from the LAN outwards.
• From Link to the LAN. Using filters here will forward or block traffic from the link inwards.
Using a variety of parameters, Advanced Filters can be used to regulate different protocols, to totally or partially
block traffic, and to control traffic between links.
Figure 5-36. Action of an Advanced Filter.
There are two modes through which filtering can be implemented: blocking and forwarding.
Blocking
The block command causes the Ethernet Extender to test every packet of data that is sent to or from the LAN.
If the packet passes the test, passage is denied.
Example:
You want to ensure that IP/UDP packets do not go on to the link in the direction of the Internet/Intranet.
Thus, you design a filter which tests each packet to see if it is an IP/UDP packet. If the packet tests positive, it is
automatically blocked.
Forwarding
The forward command works in the same way as the block command. However, with forwarding, if the packet
passes the test, it is allowed passage to or from the LAN.
Example:
You want to allow a certain user on the small-office LAN to access the Internet for FTP purposes. To do this, you
create a filter to test each packet for the IP host address of the specified user and the FTP socket of the packet.
If the packet passes the test, it is forwarded to the Internet/Intranet.
Ethernet Extender
Link to LAN Filter
LAN to Link Filter
LAN
LINK
Traffic is regulated
Traffic is regulated
Summary of Contents for LB3104A series
Page 3: ......
