v1.12
Cloudberry Management – PTP Management User Manual
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1.2.8.2.6
UDP Filtering
UDP filtering is a feature which enables filtering of UDP messages on output (egress) of the
switch. The feature works on Layer 4 (Transport layer) where packets are identified as UDP
packets before they are compared to the selected filters. Individual filters can be configured
per physical switch port on UDP destination ports, UDP source ports or a combination of
these. Block or allow filters are selectable for each port individually. The UDP filtering feature
is relevant for lowering the network load on end devices which may receive undesired
network traffic. Note that some ports are prohibited from filtering.
Filter restrictions/limitations
It is not possible to set filters below port 100, all packets below port 100 flows freely through
the switch regardless of settings. Ports below 1024 are reserved for known protocols, and
please note that setting filters in this range will cause malfunction of these protocols. A
warning will also be issued if ports below port 5000 are configured. There are many known
protocols in this area which will malfunction if a filter is set in this range. The IPSet program
uses two ports: 5123 and 5124, which also are prohibited from filtering. In this way it is always
possible to find the device via IPSet regardless of any filters set.
Filter modes
There are two main filter modes: “Allow” and “Block” filters. The Allow filter will only allow the
UDP packets which match the configured filters whereas the Block filter will discard all
packets matching the configured filters.
It is possible to filter on:
1) UDP destination ports
2) UDP source ports
3) A special combination where one destination port is set together with multiple source
ports.
These selections are available for both for Allow and Block filtering. Filtering on source ports
may be dangerous since UDP source ports are randomly provided by the operating system
for several protocols.
Allow filtering
Special caution is needed when selecting the Allow filters, since they will block every UDP
packet which is NOT configured. WARNING: If an Allow filter is set on the physical port which
the computer running IPSet is connected to the switch, the device and every device behind it
is only searchable and not configurable. It is possible to reset to factory settings and change
IP address, but the PTP settings are inaccessible.
Block filtering
The block filter discards all packets which match the filters. All other UDP packets will be sent
through the switch.
Troubleshooting
If a filter is set unintentionally such that the filter blocks traffic which was not intended, it is
always possible to search for the device and reset to factory default settings by selecting “Set
default settings”:
