The backlash against Skype is gathering momentum with the announcement of a product that hunts for and aggressively blocks communication from the program.

Ipoque’s new add-on filter for the company’s PRX Traffic Manager PRX-250 system is another symptom of a change in attitude towards the ever-spreading VoIP client among some businesses.

According to Leipzig-based Ipoque, Skype posed a number of security problems for networks. These ranged from published vulnerabilities that opened networks to security risks, the consumption of bandwidth, and the fact that the current client used strong encryption – an information and regulatory risk in certain environments.

Company CEO, Klaus Mochalski, said that the latest version of Skype had deliberately been engineered to be as difficult to track as possible using a serverless P2P design, and this had required Ipoque to invest time in recognising the way that Skype calls initiated client connections. Despite the difficulties, he was confident the module would stop Skype traffic in every instance.

Skype was also adept at bypassing firewalls, using unusual ports and ports used by legitimate traffic such as https.

The Traffic Manager hardware could be used to manage a range of other P2P programs in addition to Skype, including instant messaging, SIP-based VoIP clients, and a plethora of file-sharing programs. Being based on a transparent bridge-based approach, the system imposed no configuration or latency issues for network administrators.

The module had been sold to undisclosed customers, already, Mochalski indicated.

“We have had enquiries from companies doing work for US government agencies”, he said. He suggested - but could not confirm sources – that the US government was looking for ways of reliably blocking Skype traffic in times of national security as a way of stopping terrorist communication.

Pricing started at $2,971 for the PRX-250 unit with 1-year's updates, with additional software blocking modules priced individually.