DO0281R00
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10 Errors and problems
Problem
Solution
No link between the
devices.
The TX and RX lines are interchanged between the
ports (crossover). If the used devices do not have Auto-
MDI-X, a crossover cable has to be used on one side.
Wireshark does not show
all packets.
In the "Capture > Options" configuration dialog, activate
"Capture packets in promiscuous mode". Some network
cards filter out certain packet types that Wireshark is
unable to display. This can be solved only by using a
card from a different manufacturer.
Wireshark does not show
large packets.
TAP attaches 20 bytes of additional information to the
packets. If large packets containing more than 1480
bytes of useful data are transmitted, the maximum
packet length of 1500 bytes (1518 bytes, incl. Ethernet
header and CRC) is exceeded and the packet will
normally be rejected by the Ethernet card in the
computer on which Wireshark is running. This can be
avoided by activating "Jumbo packets" in the driver.
Wireshark shows packets
as faulty.
If the TAP plugin is not activated, Wireshark (or a
different analysis program without TAP plugin) might
show a checksum error. This is due to the additional
data that TAP CURIOUS has attached to the data
packet.
You can ignore this error message.
Wireshark shows
additional packets.
It could be that the PC on which Wireshark is running is
sending additional broadcasts over the used interface.
You can avoid this by deactivating all elements (Client
for Microsoft networks, Internet protocol (TCP/IP), etc.)
in the LAN adapter properties under Windows.
Negative time stamp:
If the network becomes overloaded, the network card
may not output the frames in the correct sequence.
This can be because the number of RSS queues in the
network card is greater than one. To remedy the
problem, the number of queues must be set to one.
Changed port number
(auto crossover)
Due to the auto crossover function, the cable
assignment through the listening devices is random. As
a result, frames from device A (connected to Con A
port) can be detected when frames have been received
on Con B port.
Errors and problems
