Warning This workaround may make a computer or a network more vulnerable to attack by malicious users or by malicious software such as viruses. We do not recommend this workaround but are providing this information so that you can implement this workaround at your own discretion. Use this workaround at your own risk.
Warning If you use this setting, you will break sender check for the whole SMTP virtual server. Because Anonymous authentication is enabled on the SMTP Virtual Server, sender check is disabled. This means that mail will be accepted on this Virtual Server regardless of who the sender is. Identity theft can occur in this case. Therefore, if you intend to check senders by using basic authentication, do not use this setting. If the
SmtpIpRestrictionFlag is turned on, an authenticated user can submit mail from an address that they do not own. Use this setting with caution.
Typically, mail administrators want Microsoft Exchange Server to receive anonymous mail submissions from hosts such as other mail gateways or application servers that must deliver mail. However, these hosts cannot be configured to use authenticated Simple Mail Transfer Protocol (SMTP). Instead, the mail administrators create a dedicated, anonymous virtual server that has the connection control configured to enable connection only from those specified hosts.
When you troubleshoot mail issues, multiplying virtual servers on Exchange Server can be difficult. Therefore, Microsoft IT has published a white paper that describes how to make the connection control settings relevant only for anonymous connections. This configuration enables you to use an existing virtual server to let anonymous connections from some IP addresses. Additionally, you can maintain access from all authenticated client computers.
You can use an existing SMTP virtual server to do the following tasks: