Infostrada is one of the biggest Internet Access Providers (IAP) in Italy. Barracuda is a software filter that analyzes all the email messages entering the network of an organization in order to block spam, viruses and similar. Whenever an Infostrada customer (but it may happen with other IAPs too, keep reading!) sends an email message to somebody “protected” (possibly without knowing it, because the filter is installed by an administrator) by Barracuda, something can happen that may create actual problems both to the sender and to the receiver.