To allow the network PCs to communicate with the Sophos Control Center you need to open some ports on the SBS 2008 box. Issue these commands from the CMD prompt
netsh firewall add portopening TCP 8192 "Sophos Management"
netsh firewall add portopening TCP 8193 "Sophos Management"
netsh firewall add portopening TCP 8194 "Sophos Management"
netsh firewall add portopening TCP 8081 "Sophos quarantine digest"
