Hola y Saludos
	 
	Te aconsejo que crees un SPF record para que tu servidor sea aceptado en otros ISP providers, de esta manera te veran como servidor de correo legitimo.
	 
	http://www.openspf.org/SPF_Record_Syntax
	Evaluation of an SPF record can return any of these results:
	
		
			| Result | Explanation | Intended action | 
		
			| Pass | The SPF record designates the host to be allowed to send | accept | 
		
			| Fail | The SPF record has designated the host as NOT being allowed to send | reject | 
		
			| SoftFail | The SPF record has designated the host as NOT being allowed to send but is in transition | accept but mark | 
		
			| Neutral | The SPF record specifies explicitly that nothing can be said about validity | accept | 
		
			| None | The domain does not have an SPF record or the SPF record does not evaluate to a result | accept | 
		
			| PermError | A permanent error has occured (eg. badly formatted SPF record) | unspecified | 
		
			| TempError | A transient error has occured | accept or reject | 
	
	 
	 
	Examples:
	"v=spf1 mx -all"
	Allow domain's MXes to send mail for the domain, prohibit all others.
	"v=spf1 -all"
	The domain sends no mail at all.
	"v=spf1 +all"
	The domain owner thinks that SPF is useless and/or doesn't care.
	 
	Suerte