public bool IsDomainExists(string name) { if (!IsAdmin) { throw new SecurityException("Need admin privileges."); } if (string.IsNullOrEmpty(name)) { throw new ArgumentException(@"Invalid domain name.", "name"); } if (name.Length > 255) { throw new ArgumentException(@"Domain name exceed limitation of 255 characters.", "name"); } if (!Parser.IsDomainValid(name)) { throw new ArgumentException(@"Incorrect domain name.", "name"); } var domainName = name.ToLowerInvariant(); var isExists = MailServer.IsDomainExists(domainName); return(isExists); }