Do I need a second firewall?

[Mike@LG]

Hi. I have two PC's, one is running XP Pro (host) and the other Win2000 Pro
(client).

Both machines have are fitted with a 3Com Etherlink 10/100 PCI NIC
(3C-905-TX) Network Card. The Host PC has an internal PCI ADSL modem. The
Host PC has internet connection sharing enabled for the Client. The Host
PC, (by default) XP has automatically configured the Network Card's IP
address to 192.168.0.1, the Client manually configured to 192.168.0.2 with
the Default gateway set to 192.168.0.1. I can happily transfer files back
and forth and the internet works fine on both machines. Now, here is my
crunch question. The Host PC has Norton Internet Security 2003 Professional
installed. Do I need to install a firewall on the second (Client) PC?
(Note: Both PC's are up to date with all necessary updates/service packs
from Windows Update). How safe is the Client PC when the Host is connected?
Info greatly appreciated. TIA.

Mike

 

[Piniongear]

In my opinion Mike, I think you are quite safe. By patching regularly
and running a decent firewall, you make yourself quite safe. In my
experience, enabling the Internet Connection firewall that ships with XP is
another measure of safety. It's a low-quality firewall, but it works in the
background, and is easy to set-up.A hacker would have to get through that
first, then your Norton, then find his way through your host computer and
then into your Client computer. Your average 16 year old that found a piece
of hacker code on the net is going to have a hard time. If you have a real
hacker knocking on the door, he/she will get in if they really want in. But,
what we want to do is make it hard enough that they won't bother, and you
have done a decent job of that.

Sleep easy my friend!

Howard

 

[Chuck]

Hi. I have two PC's, one is running XP Pro (host) and the other Win2000 Pro
(client).

Both machines have are fitted with a 3Com Etherlink 10/100 PCI NIC
(3C-905-TX) Network Card. The Host PC has an internal PCI ADSL modem. The
Host PC has internet connection sharing enabled for the Client. The Host
PC, (by default) XP has automatically configured the Network Card's IP
address to 192.168.0.1, the Client manually configured to 192.168.0.2 with
the Default gateway set to 192.168.0.1. I can happily transfer files back
and forth and the internet works fine on both machines. Now, here is my
crunch question. The Host PC has Norton Internet Security 2003 Professional
installed. Do I need to install a firewall on the second (Client) PC?
(Note: Both PC's are up to date with all necessary updates/service packs
from Windows Update). How safe is the Client PC when the Host is connected?
Info greatly appreciated. TIA.

Mike

Mike,

The firewall on the host pc should protect both the host and client
from any hostile internet traffic.

Unfortunately, with a wireless LAN, you have as much possible threat
coming from the airwaves as from the internet. Even with WEP (128 bit
encryption) turned on, SSID changed from default value, and MAC
address filtering enabled (all of which you should be doing anyway), a
wardriver can penetrate your network in a couple hours by monitoring
network traffic.

The range limitation of your network is not protection either. Even
if you can barely get a connection between your host in one room and
the client in another, a wardriver with a high gain antenna could be
driving by blocks away and attach to your network.

My recommendation for a wireless LAN would be to use a separate
firewall on all computers, only share what folders are essential, and
not keep any secrets on any connected computer.

Cheers,

Chuck
I hate spam - PLEASE get rid of the spam before emailing me!
Paranoia comes from experience - and is not necessarily a bad thing.

 

[Lou Rosse]

Mike,

The firewall on the host pc should protect both the host and client
from any hostile internet traffic.

Unfortunately, with a wireless LAN, you have as much possible threat
coming from the airwaves as from the internet. Even with WEP (128 bit
encryption) turned on, SSID changed from default value, and MAC
address filtering enabled (all of which you should be doing anyway), a
wardriver can penetrate your network in a couple hours by monitoring
network traffic.

The range limitation of your network is not protection either. Even
if you can barely get a connection between your host in one room and
the client in another, a wardriver with a high gain antenna could be
driving by blocks away and attach to your network.

My recommendation for a wireless LAN would be to use a separate
firewall on all computers, only share what folders are essential, and
not keep any secrets on any connected computer.

This is good advice for anybody using a wireless LAN. He's not.

 

[Chuck]

This is good advice for anybody using a wireless LAN. He's not.

Aack. Too much coffee this morning.


Chuck
I hate spam - PLEASE get rid of the spam before emailing me!
Paranoia comes from experience - and is not necessarily a bad thing.

 

[Mike@LG]

Many thanks there Howard for your information, greatly appreciated. And
thanks also to all others who replied.

I frequently see my firewall blocking the BackDoor Sub 7 Trojan--whatever
the Trojan does I don't know. I don't have any personal info./data on
either machines but that doesn't mean I'm not concerned that if either PC
became infected with a virus/Trojan I wouldn't be concerned. I'd just
reformat the drive, reinstall Windows and start all over again. Okay,
here's a question I'm unsure about, probably silly but I'd still like it
answered. If on the Host PC (with Norton Internet Security Pro. installed)
I ping my IP address I get the 'Request Timed Out' but if on the Client PC I
ping my IP address I get a reply. Does this mean my Client PC sharing/using
the same IP address as my Host can be pinged or seen to the outside world?
P.S. I have a static IP address.