System.Net.Mail.SmtpClient.Initialize C# (CSharp) Method

        private void Initialize()
        {
            if (_port == DefaultPort || _port == 0)
            {
                new SmtpPermission(SmtpAccess.Connect).Demand();
            }
            else
            {
                new SmtpPermission(SmtpAccess.ConnectToUnrestrictedPort).Demand();
            }

            _transport = new SmtpTransport(this);
            if (NetEventSource.IsEnabled) NetEventSource.Associate(this, _transport);
            _onSendCompletedDelegate = new SendOrPostCallback(SendCompletedWaitCallback);

            if (_host != null && _host.Length != 0)
            {
                _host = _host.Trim();
            }

            if (_port == 0)
            {
                _port = DefaultPort;
            }

            if (_targetName == null)
                _targetName = "SMTPSVC/" + _host;

            if (clientDomain == null)
            {
                // We use the local host name as the default client domain
                // for the client's EHLO or HELO message. This limits the 
                // information about the host that we share. Additionally, the 
                // FQDN is not available to us or useful to the server (internal
                // machine connecting to public server).

                // SMTP RFC's require ASCII only host names in the HELO/EHLO message.
                string clientDomainRaw = IPGlobalProperties.GetIPGlobalProperties().HostName;
                IdnMapping mapping = new IdnMapping();
                try
                {
                    clientDomainRaw = mapping.GetAscii(clientDomainRaw);
                }
                catch (ArgumentException) { }

                // For some inputs GetAscii may fail (bad Unicode, etc).  If that happens
                // we must strip out any non-ASCII characters.
                // If we end up with no characters left, we use the string "LocalHost".  This 
                // matches Outlook behavior.
                StringBuilder sb = new StringBuilder();
                char ch;
                for (int i = 0; i < clientDomainRaw.Length; i++)
                {
                    ch = clientDomainRaw[i];
                    if ((ushort)ch <= 0x7F)
                        sb.Append(ch);
                }
                if (sb.Length > 0)
                    clientDomain = sb.ToString();
                else
                    clientDomain = "LocalHost";
            }
        }