D-Link DES-3250TG User Manual page 50

The target port is where information will be duplicated and sent for capture and network analysis. A network analyzer would
be attached to this port to capture packets duplicated from the source port.
It should be noted that a faster port (a 1000 Mbps Gigabit Ethernet port, for example) should not be mirrored to a slower port
(one of the 48 100 Mbps Fast Ethernet ports), because many packets will be dropped.
The following fields can be set:
D-Link DES-3250TG Standalone Layer 2 Switch
Figure 7- 8. Setup Port Mirroring window
Parameter
Source Port
None
Ingress
Egress
Both
Description
Allows multiple ports to be mirrored. These
ports are the sources of the packets to be
duplicated and forwarded to the Target port.
Selecting this option prevents any packets
from either being received or transmitted.
Selecting this option mirrors only received
packets.
Selecting this option mirrors only transmitted
packets.
Selecting this option mirrors both received
and transmitted packets.
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