With enterprise perimeter firewalls struggling to keep out the increased number of attacks, Sophos' personal firewall can help protect desktops and laptops.
The anti-virus software company already sells an anti-spam product, and the personal firewall from Agnitum is seen by analysts as a natural step towards offering wider enterprise security.
The Agnitum Outpost Pro system will be available for download from Sophos from this spring. Sophos is also planning anti-spyware and anti-adware products.
Chris Christiansen, an analyst at IDC, said, "By recognising the convergence and complexity of threats and adding a personal firewall to its offering, Sophos is providing protection at all points of the network."