Firewall Question

I am running a Linksys WRT54GS router with 2 machines attached with CAT 5
running Windows XP. One machine can access the Internet and the other
machine can't and displays the message "Internet Explorer cannot display
this web page" By playing around I discovered if I turn off the firewall on
the router I can access the Internet. Does anyone have any ideas as to what
the problem might be.

> By playing around I discovered if I turn off the firewall on the router I
> can access the Internet.

Is the windows firewall on or off on the offending computer? Leaving the
router firewall in place and turning off the windows firewall can work
wonders.

"Charlie" <(E-Mail Removed)> hath wroth:

>I am running a Linksys WRT54GS router with 2 machines attached with CAT 5
>running Windows XP. One machine can access the Internet and the other
>machine can't and displays the message "Internet Explorer cannot display
>this web page" By playing around I discovered if I turn off the firewall on
>the router I can access the Internet. Does anyone have any ideas as to what
>the problem might be.

You might want to run:
Start -> Run -> cmd <enter>
IPCONFIG
If the IP address of the 2 machines are 192.168.1.xxx, then it's
working and I don't have a clue why it's broken.

If the IP address of *ONE* of the machines is a routeable IP address
(other than 169.254.xxx.xxx), then you have successfully miswired the
CAT5 cables. Connect the "internet" or "WAN" port on the WRT54G to
the cable or DSL modem.


--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

The Windows firewall is turned off and no other firewall is running on the
system.
"rieker" <(E-Mail Removed)> wrote in message
news(E-Mail Removed) ...
>> By playing around I discovered if I turn off the firewall on the router I
>> can access the Internet.
>
> Is the windows firewall on or off on the offending computer? Leaving the
> router firewall in place and turning off the windows firewall can work
> wonders.
>
>

The machine is being assigned a valid private IP address from DHCP. When
comparing the results from the IPCONFIG command the two machines look the
same except for the IP address. Both machines can see each other and share
files. If I wire directly from the modem to the machine it can access the
Internet. I cannot access the Internet coming from the router with the
firewall turned on. I have a wireless laptop also that works fine however my
son brought over a new Dell laptop that has the exact same problem as my
second machine. Something is really goofy here.
"Jeff Liebermann" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Charlie" <(E-Mail Removed)> hath wroth:
>
>>I am running a Linksys WRT54GS router with 2 machines attached with CAT 5
>>running Windows XP. One machine can access the Internet and the other
>>machine can't and displays the message "Internet Explorer cannot display
>>this web page" By playing around I discovered if I turn off the firewall
>>on
>>the router I can access the Internet. Does anyone have any ideas as to
>>what
>>the problem might be.
>
> You might want to run:
> Start -> Run -> cmd <enter>
> IPCONFIG
> If the IP address of the 2 machines are 192.168.1.xxx, then it's
> working and I don't have a clue why it's broken.
>
> If the IP address of *ONE* of the machines is a routeable IP address
> (other than 169.254.xxx.xxx), then you have successfully miswired the
> CAT5 cables. Connect the "internet" or "WAN" port on the WRT54G to
> the cable or DSL modem.
>
>
> --
> Jeff Liebermann (E-Mail Removed)
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558

"Charlie" <(E-Mail Removed)> hath wroth:

>The machine is being assigned a valid private IP address from DHCP. When
>comparing the results from the IPCONFIG command the two machines look the
>same except for the IP address. Both machines can see each other and share
>files.

Ok, that's normal assuming that your idea of "valid private IP" is the
same as mine. (Assumption, the mother of all screwups).

>If I wire directly from the modem to the machine it can access the
>Internet. I cannot access the Internet coming from the router with the
>firewall turned on. I have a wireless laptop also that works fine however my
>son brought over a new Dell laptop that has the exact same problem as my
>second machine. Something is really goofy here.

Do you have Norton Internet Security or a similar personal firewall
installed? It will block by what it considers a LAN IP address block.
It's probably configured for a direct connection to the internet
(routeable IP's), but not for your local private IP LAN. Try
temporarily disarming the monster and try again.

Also, there are some versions of such personal firewall products that
often don't get completely uninstalled. If it had an older version of
McAfee security installed, check if there's still some residue:
start -> run -> cmd
msconfig -> startup programs

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Charlie" <(E-Mail Removed)> hath wroth:

>The Windows firewall is turned off and no other firewall is running on the
>system.

Are you sure? If you had for example Norton Internet Security
installed and configured for direct internet access, it would require
adding an additional "zone" for the local LAN IP block. If this
wasn't done, or was set to intentionally consider the local LAN as
insecure, the symptoms would be exactly as you describe. Try
installing Startup Inpsector for Windoze:
http://www.WindowsStartup.com
and see what's starting on your machine.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I downloaded the WindowsStatrup program and checked every entry. I only have
9 entries listed and everything looked correct. I am running Norton
AntiVirus 2003 but never have used Internet Security or any other similar
product. Thanks for the suggestions and if anything else comes to mind
please let me know. I will keep looking around.
"Jeff Liebermann" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Charlie" <(E-Mail Removed)> hath wroth:
>
>>The Windows firewall is turned off and no other firewall is running on the
>>system.
>
> Are you sure? If you had for example Norton Internet Security
> installed and configured for direct internet access, it would require
> adding an additional "zone" for the local LAN IP block. If this
> wasn't done, or was set to intentionally consider the local LAN as
> insecure, the symptoms would be exactly as you describe. Try
> installing Startup Inpsector for Windoze:
> http://www.WindowsStartup.com
> and see what's starting on your machine.
>
> --
> Jeff Liebermann (E-Mail Removed)
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558

The IP address on the machine is 192.168.1.101 which was issued by the DHCP
server. I even assigned a static IP address but that didn't work either. The
only product that has ever been installed on this machine is Norton
AntiVirus 2003. I also tried to boot into Safe Mode (with network) and
tried to access the Internet. Not sure if that should have worked even if
things were right. Also tried to go back one version of firmware on the
router. It didn't work. Thanks for all the suggestions Jeff.
"Jeff Liebermann" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Charlie" <(E-Mail Removed)> hath wroth:
>
>>The machine is being assigned a valid private IP address from DHCP. When
>>comparing the results from the IPCONFIG command the two machines look the
>>same except for the IP address. Both machines can see each other and share
>>files.
>
> Ok, that's normal assuming that your idea of "valid private IP" is the
> same as mine. (Assumption, the mother of all screwups).
>
>>If I wire directly from the modem to the machine it can access the
>>Internet. I cannot access the Internet coming from the router with the
>>firewall turned on. I have a wireless laptop also that works fine however
>>my
>>son brought over a new Dell laptop that has the exact same problem as my
>>second machine. Something is really goofy here.
>
> Do you have Norton Internet Security or a similar personal firewall
> installed? It will block by what it considers a LAN IP address block.
> It's probably configured for a direct connection to the internet
> (routeable IP's), but not for your local private IP LAN. Try
> temporarily disarming the monster and try again.
>
> Also, there are some versions of such personal firewall products that
> often don't get completely uninstalled. If it had an older version of
> McAfee security installed, check if there's still some residue:
> start -> run -> cmd
> msconfig -> startup programs
>
> --
> Jeff Liebermann (E-Mail Removed)
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558