public bool CheckAuthoritative(SmtpDomain domain)
        {
            AcceptedDomainEntry domainEntry = this.GetDomainEntry(domain);

            return(domainEntry != null && domainEntry.IsAuthoritative);
        }
        public bool CheckInternal(SmtpDomain domain)
        {
            AcceptedDomainEntry domainEntry = this.GetDomainEntry(domain);

            return(domainEntry != null && domainEntry.IsInternal);
        }