LAN and firewalls: Router yes; hub no?

[Jerry A]

Situation: 6 computers running WinXP Pro SP2 with a
LinkSys BEFSR41 router and a hub for the extra computers.
With only ONE of these computers, when I connected it
through the router, it saw the network just fine but when
it was on the hub, it didn't see the network. But when I
took off its SP2 firewall, it worked through the hub fine.

Questions:
* Any idea why this happened?
* When I hook the network to the Internet through a
cable modem, am I risking problems by having the firewall
down on that one computer?

Thanks for your help,
Jerry

 

[Steve Winograd [MVP]]

Situation: 6 computers running WinXP Pro SP2 with a
LinkSys BEFSR41 router and a hub for the extra computers.
With only ONE of these computers, when I connected it
through the router, it saw the network just fine but when
it was on the hub, it didn't see the network. But when I
took off its SP2 firewall, it worked through the hub fine.

Questions:
* Any idea why this happened?
* When I hook the network to the Internet through a
cable modem, am I risking problems by having the firewall
down on that one computer?

Thanks for your help,
Jerry

Is your finding repeatable? Can you demonstrate that the problem
computer can always connect through the hub when the SP2 firewall is
disabled and can never connect through the hub when the SP2 firewall
is enabled? If not, it could just be coincidence. Check the duplex
and speed settings on that computer's NIC -- automatically sensing
them doesn't always work right. The next time the computer can't
connect, try rebooting the computer and/or rebooting the hub, without
changing the firewall settings.

A computer connected to the cable modem through the router is safe,
because the router acts as a hardware firewall. A computer connected
directly to the Internet through a modem (cable, DSL, or dial-up)
needs a firewall, or it will probably be hacked within a few minutes.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

 

[Hans-Georg Michna]

Situation: 6 computers running WinXP Pro SP2 with a
LinkSys BEFSR41 router and a hub for the extra computers.
With only ONE of these computers, when I connected it
through the router, it saw the network just fine but when
it was on the hub, it didn't see the network. But when I
took off its SP2 firewall, it worked through the hub fine.

Questions:
* Any idea why this happened?

Jerry,

no, but retest. It doesn't actually sound likely.

Replace the hub with a switch, at least for a test, assuming
that it is defective, but even that sounds unlikely.

* When I hook the network to the Internet through a
cable modem, am I risking problems by having the firewall
down on that one computer?

Yes.

Hans-Georg