Every time you attempt to connect to a server using SSH, you get the following prompt:
The authenticity of host '111.222.333.444 (111.222.333.444)' can't be established.
RSA key fingerprint is f3:cf:58:ae:71:0b:c8:04:6f:34:a3:b2:e4:1e:0c:8b.
Are you sure you want to continue connecting (yes/no)?
To avoid having to type "yes" every time, use the -o option:
ssh -o "StrictHostKeyChecking no" user@host