It is always advised that one should not use two firewalls. Windows XP SP2 firewall can always be disabled, and may not give much additional power. I wanted a firewall something more than what NIS can give. Assuming that NIS cannot coexist with another firewall, I decided to go for Norton Antvirus 2007, and use another firewall. NAV 2007 has an inbound firewall(packet filter, program control, and internet worm protection). But I needed a firewall for outbound control as well. However, this adds to the dillemma of having two firewalls. I decided to install sunbelt kerio personal firewall 4. To my amazement, NAV2007 recognized SKPF4, and made necessary entries there in its configuration file, and entered it as an advanced firewall in the Norton protection center. If SKPF4 is not started, just start, and NPC would say that it is enabled. They have been workiing together peacefully so far.
Incoming connections are first processed by SKPF4, and then by NAV 2007 if they happen to reach there.
Hence, I presume one can use two firewalls if they recognize each other, and they are friends. Of course, one has to be careful with settings. Particularly, one should not meddle with
windows outgoing services which might crash the system.
-R. C. Hansdah