Internet connection sharing firewall information

  shezzer 19:17 10 Jul 2003

My son and i share the internet connection on my computer which has norton firewall installed. Does it need to be installed on both computers . cheers mike

  jazzypop 20:52 10 Jul 2003


  Gaz 25 20:59 10 Jul 2003

For full protection yes.

However your network will be protected from incoming if just the PC with Internet actually connected to it has Norton On, but to protect against trojans yes, Install on both.

  jazzypop 21:23 10 Jul 2003

I disagree.

A network is protected to a very large extent, simply by installing the MS ICS (which is in effect a NAT proxy software, and therefore allocates reserved IP addresses to both PCs). The Norton/Sygate/ZoneAlarm firewall does not give any significant additional protection to the network for *incoming* IP packets.

However, the ICS software, as well as Norton/Sygate etc, will treat any *outgoing* IP packets as valid, if they originate from the 2nd PC.

Therefore, to obtain any significant benefit for the 2nd PC on an ICS network (i.e. the PC that is not the 'gateway' PC), it is necessary to install a software firewall on that 2nd PC.

Then, and only then, any outgoing IP packets are checked to ensure that they are being sent from an 'authorised' program or process.

Remember that NAT protection only checks that IP packets have a valid originating IP address (NAT protection is provided by proxy software such as ICS, and cheaper hardware routers).

Software firewalls check that a program has permission to send/receive.

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