Question & Answer
Question
Generally, "netstat -an“ shows the state of all socket connections.
# netstat -an
Active Internet connections (including servers)
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 *.111 *.* LISTEN
tcp4 0 0 100.300.0.35.10022 100.300.0.173.45521 ESTABLISHED
tcp4 0 0 100.300.0.35.10022 100.300.0.173.21028 ESTABLISHED
tcp 0 0 *.657 *.* LISTEN
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 *.111 *.* LISTEN
tcp4 0 0 100.300.0.35.10022 100.300.0.173.45521 ESTABLISHED
tcp4 0 0 100.300.0.35.10022 100.300.0.173.21028 ESTABLISHED
tcp 0 0 *.657 *.* LISTEN
However, sometimes, we can see some values on Recv-Q and Send-Q.
What does that mean?
Cause
Answer
Recv-Q:
High Recv-Q means the data is put on TCP/IP receive buffer, but the application does not call recv() to copy it from TCP/IP buffer to the application buffer. Customer can check the application listening the port, and see if it is working as expected. For example, if you saw Recv-Q in the following connection:
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp4 3223 0 11.10.32.24.8002 11.10.32.12.64672 ESTABLISHED
Customer should check the application listening the port 8002.
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp4 3223 0 11.10.32.24.8002 11.10.32.12.64672 ESTABLISHED
Customer should check the application listening the port 8002.
Send-Q:
High Send-Q means the data is put on TCP/IP send buffer, but it is not sent or it is sent but not ACKed. So, high value in Send-Q can be related to server network congest, server performance issue or data packet flow control, and so on.
Please note: The send and receive queue sizes are shown in bytes.
[{"Type":"MASTER","Line of Business":{"code":"LOB08","label":"Cognitive Systems"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SWG10","label":"AIX"},"ARM Category":[{"code":"a8m0z000000cvzIAAQ","label":"Networking"}],"ARM Case Number":"","Platform":[{"code":"PF002","label":"AIX"}],"Version":"All Versions"}]
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Document Information
Modified date:
31 December 2021
UID
ibm16537582