Installing a firewall on a network

[magicalheat]

I am trying to set up zone alarm on my network but have been unsuccessful. The host computer (Win XP) has access to the internet but the other computers on the LAN don't have access when the firewall is in place. I have looked in the help section of zone alarm but the instructions are unclear (well they are to a novice like me!) Can anyone give me some basic instructions that will resolve the issue? Thanks

[Greenstead]

Can you clarify how the PCs are connected?

Presumably you are sharing the internet connection by using ICS.

[cszeto]

If you are running ICS, the NIC to your internal network connecting the other systems, needs to be opened up for unrestricted access. Otherwise the firewall will treat the internal network as a hostile network and block all incoming traffic from your other systems rendering ICS non-functional.

I just had some run-ins with the ZoneAlarm product...

http://forums.practicallynetworked.com/showthread.php?threadid=2077

XP also has a capable firewall built-in. It does not have any alerts or logs, but it does the job...

[magicalheat]

Thank you both for replying.

Are the computers sufficiently secure with the Win XP firewall or does it just provide minimal security?

I'm using Belkin wireless 802.11 Ad Hoc to connect the pc's. The ICS is running. How do I enable the NIC with the firewall so that both pc's can use the internet?

[cszeto]

The XP firewall is a simple, but an effective firewall for most uses. It was successful in averting the latest "mblaster" attacks. It mainly filters out incoming traffic rather then all traffic as in the approach by the other personal firewalls.

To protect an ICS connection with the XP firewall, just enable it on the NIC or dial-up profile that is connected to the ISP/Internet.

You can also enable the XP firewall on the individual machines too, since it mainly filters incoming traffic, but you will need to additionally configure the firewalls for file and print sharing between the systems (if you need that functionality) in that case. If you go that route, just keep in mind that you still do not want to enable the firewall on the NIC that is connected to the other machines on the ICS host (unless you are comfortable with configuring the firewall accordingly).

[Greenstead]

The purpose of zonealarm, if you already have a firewall like ICS or a NAT router, is to detect/stop unexpected outgoing connections from worms or trojans. In zonealarm you have an internet zone and a trusted zone. You need to place your subnet in the trusted zone (192.168.0.0 mask 255.255.255.0)