Logs need to be monitored to check for unusual traffic activity and the software must be updated. The firewall should also be routinely tested to make sure it is performing adequately. Having an unmonitored firewall can almost be worse than not having one at all as it may lull you into a false sense of comfort about being secure from hackers. Before meeting with vendors, get a sense for how the Internet is used in the office. This will affect your firewall setup.
Most vendors prefer a particular type of firewall solution.
To make sure it's right for you, ask lots of questions about how widely it is installed, what types of businesses it is best suited for and why they prefer that firewall over other options. Also ask about the firewall vendor's support hours, the typical turnaround time for response, and the upgrade or patch policy. Find out how much time the vendor spends defining what the security policy should be with previous clients, and how effective the consultant is in explaining the technical details. Probe for diligence by checking the amount of testing and follow up on what the consultant performs. Finally, learn how quickly the vendor responds in event of a firewall crash, which will effectively slam the door between your office and the Internet.