A number of folks are talking about a significant uptick in Barracuda IP blocks over the last few days. These blocks appear to be affecting wide ranges of IPs across multiple networks.
Folks have been reaching out to Barracuda through their unblocking form. Many of them are not receiving answers, but some are getting answers that say they may be old listings, and there is no current data to support the listing.
This issue is ongoing, as I was writing this post another ESP posted that they were seeing widespread listings affecting multiple customers. As of 1500 UTC folks are still seeing listings populate.
I did reach out on Twitter and their CS folks are passing the reports on to the correct people inside the company. Updates as I get them.
Update (1900 UTC): Barracuda support is actively responding to issues on Twitter. If anyone is actually a Barracuda customer, they’d like a case filed with support about this. Posters on mailop say Barracuda is aware of the issue and are trying to fix.
June 19: The blocks should be resolving now. More information on the update blog post.