docsDevFilterIpTable
1.3.6.1.2.1.69.1.6.4
An ordered list of filters or classifiers to apply to
IP traffic. Filter application is ordered by the filter
index, rather than by a best match algorithm (Note that
this implies that the filter table may have gaps in the
index values). Packets which match no filters will have
policy 0 in the docsDevFilterPolicyTable applied to them if
it exists. Otherwise, Packets which match no filters
are discarded or forwarded according to the setting of
docsDevFilterIpDefault.
Any IP packet can theoretically match multiple rows of
this table. When considering a packet, the table is
scanned in row index order (e.g. filter 10 is checked
before filter 20). If the packet matches that filter
(which means that it matches ALL criteria for that row),
actions appropriate to docsDevFilterIpControl and
docsDevFilterPolicyId are taken. If the packet was
discarded processing is complete. If
docsDevFilterIpContinue is set to true, the filter
comparison continues with the next row in the table
looking for additional matches.
If the packet matches no filter in the table, the packet
is accepted or dropped for further processing based on
the setting of docsDevFilterIpDefault. If the packet is
accepted, the actions specified by policy group 0
(e.g. the rows in docsDevFilterPolicyTable which have a
value of 0 for docsDevFilterPolicyId) are taken if that
policy group exists.
Logically, this table is consulted twice during the
processing of any IP packet - once upon its acceptance
from the L2 entity, and once upon its transmission to the
L2 entity. In actuality, for cable modems, IP filtering
is generally the only IP processing done for transit
traffic. This means that inbound and outbound filtering
can generally be done at the same time with one pass
through the filter table.