Request feedback on my STMP iRule

But the client can change the string in the initiation string that is supposed to be its domain name anytime it wants, since you effectively have an open relay.

I have been working on an irule that will enforce validation of the domain name in the client initiation string. But I have not yet been able to find a suitable environment to test it properly, or at all at the moment. I will share it once I have tested it to my satisfaction.