Data caching DNS Error

[YuZhe-CN]

I have 3 virtual machines (2 servers and 1 client). After downloading docker images, I run the following line
$ docker exec -it dc-client /bin/bash /entrypoint.sh --m="S&W" --S=2 --D=4096 --w=2 --T=1. The result I get is DNS Error.
IPs:

• Server 1: 192.168.100.31
• Server 2: 192.168.100.32
• Client: 192.168.100.33