"can't connect 99" Displayed During a Stress Test on the Client

Symptom

The message "can't connect 99" is displayed when the client is running a stress test.

Key Process and Cause Analysis

The client failed to connect to a server.

Conclusion and Solution

Adjust kernel parameters on the client and server to optimize the performance of TCP connections.

1. Open the kernel parameter file.

   vim /etc/sysctl.conf

2. Press i to enter the insert mode and add the following parameters to the file:

   net.ipv4.tcp_tw_reuse = 1
   net.ipv4.tcp_tw_recycle = 1
   net.ipv4.tcp_syncookies = 1
   net.ipv4.ip_local_port_range = 1024      65500

3. Press Esc, type :wq!, and press Enter to save the file and exit.
4. Make the configuration take effect.

   sysctl -p