Probably the most popular personal firewall, ZoneAlarm is easy to deploy and use. Setting it up is simple and the default settings for Internet and intranet security are good enough for a normal user. For the first few days after installation, you will be prompted for a lot of applications trying to access the Internet. Once you say ‘yes’ to them and also ask ZoneAlarm to remember them, you will not be prompted again. Any suspected trojans can thus be traced and only trusted applications allowed access. These access rights can be modified later also. The application starts up with Windows and sits in the system tray. The convenient icon in the tray also lets you keep an eye on network activity by means of a red and green level-indicator.
Both incoming and outgoing connections are monitored. So any harmful port scans from the void are averted and also logged with their IP and the port they are trying to access. Another useful feature is called MailSafe e-mail protection. This automatically quarantines e-mail attachments like *.com, *.exe, or *.pif. You can also add more attachments to be monitored.
The firewall comes in two flavors, free and Pro and is free for individual and non-business use.
Ashish Sharma at PCQ Labs