Chapter 2 - Features set
User Manual
R5000 series - Web GUI
68
Furthermore, a filter may be applied to all inbound packets or only to packets arriving
via a specific interface. Each received packet is checked against all filters in the
order they are put in the set.
The first filter that matches the received packet determines how the packet will be
treated. If the filter is an accept filter, the packet is accepted, otherwise it is rejected.
If the packet matches no filter in the set, or if the set is empty, the packet is accepted.
NOTE
The rejected packet will be discarded without notification to the sender.
2.4.6.1. Packet filtering rules
Every packet entering a router passes through a set of input filters (blocking filters).
The packets accepted by the input filter set are further processed by the IP layer of
the router kernel. If the IP layer determines that the packet should go further and not
landing here, it hands the packet to the set of outgoing filters (forwarding filters).
Information on packets rejected by any filter is displayed on the
operator’s terminal
and the packets themselves are discarded without any notice to their sender.
A packet, "advancing through" a set of filters, is checked by every filter in the set,
from the first one till the end of the set, or until the first matching filter. The algorithm
is the following:
1.
If the filter set is empty, the packet is accepted
2.
Otherwise, the first matching filter decides what to do with the packet. If it is an
accept filter, the packet is accepted. If i
t’s a reject filter, the packet is rejected
(discarded)
3.
If no filter has been found that matches the packet, it is accepted
2.4.6.2. IP Firewall parameters
In the IP Firewall parameters section, you can view the IP Firewall rules that are
already created; you can create a new rule for the current switch group by pressing
the «Add Rule» button, or you can permanently remove the rule from the
configuration by pressing the «Remove Rule» button.
IP firewall rule
parameter
Description
Action
Set the action for the rule: permit/deny/pass:
-
“Permit” - the packet will be processed by the system
(ignoring other firewall rules)
