3Com SuperStack 4 Configuration Manual page 97

Troubleshooting IP
Performance
Fault: IP layer protocol works normally but TCP and UDP cannot work normally.
In the event of such a fault, you can enable the corresponding debugging
information output to view the debugging information.
Use the
■ terminal debugging
to the console.
Use the command
■
trace the UDP packet.
The following are the UDP packet formats:
UDP output packet:
Source IP address:202.38.160.1
Source port:1024
Destination IP Address 202.38.160.1
Destination port: 4296
Use the
■ debugging tcp packet
trace the TCP packets.
Operations include:
[SW5500]terminal debugging
<SW5500>debugging tcp packet
Then the TCP packets received or sent can be checked in real time. Specific packet
formats include:
TCP output packet:
Source IP address:202.38.160.1
Source port:1024
Destination IP Address 202.38.160.1
Destination port: 4296
Sequence number :4185089
Ack number: 0
Flag :SYN
Packet length :60
Data offset: 10
command to output the debugging information
debugging udp packet
command to enable the TCP debugging to
IP Performance Configuration
to enable the UDP debugging to
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