Efficient Networks 5100 Series - Manual (Page 117)

SpeedStream Router User Guide
Filter Configuration window, the Current IP Filter Rules table refreshes with the new rules set. You
can edit, add or delete this new set of rules.
Rule Numbering
If you select a specific Firewall Level (e.g., Low) and then examine the list of rules displayed in the
Current IP Filter Rules table, you will notice that the numbers start at xx20; e.g., Low starts at 120,
not 100. The numbers preceding xx20 (1-19) are skipped to allow you extra space at the front of the
list to add new rules. Additionally, the preconfigured rules are not consecutively numbered - Low, for
example, is numbered as 120, 122, 124 – allowing you to easily interject new rules between the
existing ones.
Important! The rule numbers represent the priority with which the rules will be applied in filtering IP
packets. Consequently, rule number 120 would be applied before rule number 122. If, for example,
rule 120 denies all inbound traffic, it would render all other inbound rules useless – no inbound traffic
allowed!
This numbering/priority scheme applies independently to the two categories of rules, inbound and
outbound. Inbound rules are applied only to inbound packets; outbound rules are applied only to
outbound packets.
The display of rules in the table is ordered by the Direction category. Inbound rules are displayed
first; outbound rules display second.
DHCP (Dynamic Host Configuration Protocol)
The router provides two user-configurable Dynamic Host Configuration Protocol (DHCP) modes:
DHCP server (enabled by default from the factory) and DHCP relay agent.
DHCP Relay
The router can be configured to operate as a DHCP relay agent. This allows local machines on the
LAN to acquire their IP addresses via DHCP requests and replies that are forwarded through the
router to/from a DHCP server on the WAN. In this case, the DHCP requests are forwarded to a
specific DHCP server on the WAN network and the DHCP reply is forwarded back to the LAN
network.
The DHCP relay agent can be configured with a Primary and a Secondary DHCP Server IP address.
The Secondary address is only used if the Primary is unreachable. Any DHCP requests that are
received by the router are relayed to the Primary DHCP server at the specified IP address.
This DHCP server is then responsible for assigning the DHCP information to the DHCP client.
Typically, this DHCP server will exist in the WAN space.
DHCP Server
When operating as a DHCP server, the router will dynamically assign IP addresses to LAN nodes.
The DHCP server verifies a device’s identity, leases it an IP address for a predetermined period, and
reclaims the address for reassignment at the end of the lease period. The DHCP server supports
DHCP client hosts on the LAN side only. The router will ignore all DHCP requests that arrive from
the WAN interface.
Note You have the option to change the router’s Ethernet IP address without rebooting the router. If
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