The following example shows a Postfix SMTP VRFY verifier that establishes up to 10 simultaneous connections to the SMTP servers on hosts 220.127.116.11 and 18.104.22.168. Each time a new connection is required, the application alternates the host.
If the connection to the host chosen by the application fails (or does not respond within ten seconds), then the application tries the other host. Only if all hosts fail will the command that requires the connection fail.
<Vrfy version = "101.4635"
name = "My SMTP VRFY Verifier"
uid = "64378E86-A459-11DD-1273-09173F13E4C5">