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FILT-MEN.HPE
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Help: filter menu 01.12.93
In the default configuration Net-Control receives the entire
network traffic. It can be useful however, to make a restriction.
This is possible by changing the receivemode of the Ethernet Box
(menu point: ⌠Packets to analyse:⌡).
More complex restriction is possible by special filters..
Herewith is to be distinguished between hardware- and
software-filters.
≤Hardware filters≥ have the advantage, that these cause no additional
processor power for filtering on the Ethernet Box. Thus no packets can
be lost and you can be sure, that all data of the network traffic is
recorded. On the other side hardware filters are indeed relatively
unflexible. You can define (in addition to the real address of the
box) 4 hardware adressfilters for the Ethernet Box. If you input such
a filter and activate it, the box will only process those packets,
which are sent ≤to≥ this address. The individual hardware filters are
put together by a logical ≤or≥, so that you can maximally filter the
traffic sent to 5 different ethernetaddresses by hardware.
≤Software filters≥ can extend to other areas as the destination
address of the ethernetpackets. Net-Control gives you the possibility
to define addressfilter or general filters.
An ≤adressfilter≥ can be set, so that all packets ≤from≥, all packets
≤to≥ or all packets ≤from and to≥ this address are filtered out.
If the address is in the list of known addresses, you don't have
to input the hardwareaddress manually, but you can select it from the
address list (menu: ⌠Select from addresslist⌡). This is not possible,
if there is undefined address filter.
Completely ≤general filters≥ are defined by entering ≤where≥ (i.e.
at which offset in the ethernetpaket) ≤which≥ data should be in a
packet, so that this packet is accepted. If youe want to filter out
the traffic between two ethernet stations, which are in the list of
known addresses you can use the menu entry ⌠Select from addresslist⌡.
You are asked to select two addresses from the list and Net-Control
defines automatically two general softwarefilters (for each direction
of packet flow one filter). This is not possible, if there are no two
consecutive undefined general filters.
In all software filters you can use ⌠**⌡, to indicate, that this
byte is not considered (don't care character).
The individual software filters (both address - as well as general
filters) are joined through a logical ≤or≥. If you use however hard-
and software filters, so exists between these two kind of filters an
≤and≥ connection!
≤Saving filter definitions:≥
All filter definitions can be stored in special files with the
extension ⌠.FLT⌡. If you use the defined filters for the normal
Net-Control data sampling, you must pay attention, that each filter
is activated (marking ⌠filters: on⌡ and that the global switches
hardware filters and/or software filters are set to ⌠active⌡.
Otherwise the filters are not set before the sampling of data
starts.
You can use the filters however also for special tasks, by defining
the filters, ⌠loading them in the ethernet box⌡ and switching to
the ⌠terminal⌡-mode. (This all is done automatically under the
menu entry ⌠Terminal-Watch Mode ⌡). So you can produce e.g. with
the watchmode of the Ethernet Box a download of filtered Ethernet data.