We have implemented the V600 Email Security Gateway and are strictly using it as an SMTP relay (outbound only) for now and is accessible internally only.
Previously we had an issue with an application that would send emails (these emails had no attachment of any sort) and those emails would never appear in the Barracuda, nor were they logged anywhere in the system that I could find. The issue turned out to be a timeout occurring when resolving the domain name externally, so it turned out that the domain needed to be removed from the Domain Manager, and then it started working as it should as this timeout no longer occurred; this resolution was arrived at by Barracuda support after they ran a packet capture.
Also, it should be noted that Barracuda support has temporarily removed the function that checked for the domain and that also resolved the issue with the silently dropping emails, but we had them leave it place as we weren't sure of the potential ramifications down the road.
The issue we are now having is of the same type, our application dev team is writing a new application and we are seeing the same type of behavior, the emails get sent, intermittently the application writes an obscure error in the logging, but the Barracuda never has any record of the email ever hitting it, and the dev team is confident that the actual send is working as it should.
Is there any way of getting the Barracuda to log these silently dropped connections vs. having to get support involved and setup a packet capture, as this issue is sporadic and unpredictable as to when it will occur?