Are there any issues with using (…) anti-virus software and ORF together?
This depends on the anti-virus software. Many anti-virus gateway software (such as McAfee WebShield) works as an SMTP proxy, receiving emails on port TCP/25 and forwarding them to the Exchange server. This may cause issues with the Before Arrival filtering. Anti-virus software also often integrate with Exhange using VSAPI, which does not affect ORFs filtering. The issue you may experience is that emails are not blocked and all emails seem to come from the IP address of the anti-virus gateway. For explanation, see Q: Before Arrival filtering does not seem to work, any ideas? On Arrival filtering is not affected by this, so if you experience the issue above, you can choose to use On Arrival filtering only or to install ORF to a front-end server.
