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IP problem with WRT54G router

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  • Laptops
  • Routers
  • WiFi
  • Wireless Networking
Last response: in Wireless Networking
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Anonymous
a b D Laptop
November 10, 2004 8:17:37 PM

Archived from groups: alt.internet.wireless (More info?)

We have a very simple setup: Comcast Surfboard (RCA) cable modem to
WRT54G router. 2 laptops with wireless cards (one 802.11b, the other
802.11g).

Problem: when my husband either shuts down his laptop (with the
802.11g card) or disconnects his VPN tunnel without shutting down his
laptop, my laptop loses its connection. Rebooting my PC doesn't help.
What cures the problem (every time) is to reboot the cable modem, then
plug the router back in. It appears that something goes wrong with IP
addressing.

From a look at the Linksys firmware download information, it doesn't
appear this is a known/resolved problem. Could I have a problem with
settings? Is this something I can work around? Do I have to buy an
802.11g card for my laptop to fix this?

Thanks for any pointers!
Melissa

More about : problem wrt54g router

Anonymous
a b D Laptop
November 11, 2004 9:21:34 AM

Archived from groups: alt.internet.wireless (More info?)

does it happen when he is not using the vpn, jsut normal web surfing?


"Melissa" <melissa_webster@comcast.net> wrote in message
news:b81647de.0411101717.74378136@posting.google.com...
> We have a very simple setup: Comcast Surfboard (RCA) cable modem to
> WRT54G router. 2 laptops with wireless cards (one 802.11b, the other
> 802.11g).
>
> Problem: when my husband either shuts down his laptop (with the
> 802.11g card) or disconnects his VPN tunnel without shutting down his
> laptop, my laptop loses its connection. Rebooting my PC doesn't help.
> What cures the problem (every time) is to reboot the cable modem, then
> plug the router back in. It appears that something goes wrong with IP
> addressing.
>
> From a look at the Linksys firmware download information, it doesn't
> appear this is a known/resolved problem. Could I have a problem with
> settings? Is this something I can work around? Do I have to buy an
> 802.11g card for my laptop to fix this?
>
> Thanks for any pointers!
> Melissa
Anonymous
a b D Laptop
November 11, 2004 11:53:37 AM

Archived from groups: alt.internet.wireless (More info?)

On 10 Nov 2004 17:17:37 -0800, melissa_webster@comcast.net (Melissa)
wrote:

>We have a very simple setup: Comcast Surfboard (RCA) cable modem to
>WRT54G router. 2 laptops with wireless cards (one 802.11b, the other
>802.11g).
>
>Problem: when my husband either shuts down his laptop (with the
>802.11g card) or disconnects his VPN tunnel without shutting down his
>laptop, my laptop loses its connection.

Could you be more specific on what "loses its connection" means? Does
it mean:
1. Loses RF signal strength?
2. Disconnects the radio (no SSID)?
3. No route to the router? (Can't ping router)
4. No route to the internet? (Can't surf)
5. No DNS? (can surf by IP address, but not by name)

>Rebooting my PC doesn't help.
>What cures the problem (every time) is to reboot the cable modem, then
>plug the router back in. It appears that something goes wrong with IP
>addressing.

Weird. Assuming the WRT54G has not gone insane, the only way I could
induce a 2nd laptop to go comatose when the 1st laptop is disconnected
is if something in the 2nd laptop is going *THROUGH* the 1st laptop.
Possibilities are:
1. 2nd laptop connection to the internet is going through the VPN to
a corporate connection at some remote connection.
2. 2nd laptop is setup to use ICS (Internet Connection Sharing) or
some type of Proxy Server running on the 1st laptop.
3. Is there any VPN client software (PPTP or IPSec) running on the
2nd laptop? If, yes, turn it off and try again.

Do any of the above sound familiar?

>From a look at the Linksys firmware download information, it doesn't
>appear this is a known/resolved problem. Could I have a problem with
>settings? Is this something I can work around? Do I have to buy an
>802.11g card for my laptop to fix this?

The fact that it works at all means that it's probably in the settings
and not in any hardware issues. No need to buy anything.

However, figuring out exactly what's misconfigured is gonna be rough.
Can you supply some information here?

1. Turn off the 1st laptop, reboot or power cycle everything, and see
if the 2nd laptop works by itself (1st laptop off). If it works, then
it's probably properly configured correctly. If not, then it's time
to untangle the network settings. I won't offer any suggestions until
the culprit is better identified.

2. In the above arrangement (laptop #1 off), run:
Start -> Run -> cmd
IPCONFIG
Record the IP address and the Gateway address. The gateway address
should be the address of the WRT54G. If not, you have something
radically misconfigured on laptop #2.

3. Now, turn on the 1st laptop and run it as you would normally.
Reboot laptop #2 *AFTER* laptop #1 has done the VPN thing and
connected normally. Is the IP address and gateway the same as in test
#2? If not, then laptop #2 is either getting its DHCP assigned IP
address from an alien spaceship, through the VPN from some corporate
server, or from laptop #1. Getting it through the VPN will show up as
having TWO IP addresses, one of which comes from the router, the other
from the VPN. If so, contact the corporate LAN admin and ask for info
how how to temporarily disarm the VPN on laptop #2.

4. My guess(tm) is that you have VPN software configured on both
machines to use identical logins and authentication. When connected,
your actual packets are not going through the Comcast CMTS gateway,
but going through the VPN through the corporate server pretzel. When
either laptop intentionally disconnects or logs out of the corporate
VPN, both connections through the VPN drop resulting in no access.
Laptop #2 apparently isn't smart enough to switch the default route
from the corporate VPN gateway, back to the WRT54G.

That should be enough for now...

--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Related resources
Anonymous
a b D Laptop
November 12, 2004 2:56:25 AM

Archived from groups: alt.internet.wireless (More info?)

I have read a lot of posts about troubles with the combination Linksys + VPN
passthrough
See e.g. http://www.hansenonline.net/Networking/LinksysNews.html

More recent firmware versions do promise improvements though...

"Melissa" <melissa_webster@comcast.net> wrote in message
news:b81647de.0411101717.74378136@posting.google.com...
> We have a very simple setup: Comcast Surfboard (RCA) cable modem to
> WRT54G router. 2 laptops with wireless cards (one 802.11b, the other
> 802.11g).
>
> Problem: when my husband either shuts down his laptop (with the
> 802.11g card) or disconnects his VPN tunnel without shutting down his
> laptop, my laptop loses its connection. Rebooting my PC doesn't help.
> What cures the problem (every time) is to reboot the cable modem, then
> plug the router back in. It appears that something goes wrong with IP
> addressing.
>
> From a look at the Linksys firmware download information, it doesn't
> appear this is a known/resolved problem. Could I have a problem with
> settings? Is this something I can work around? Do I have to buy an
> 802.11g card for my laptop to fix this?
>
> Thanks for any pointers!
> Melissa
Anonymous
a b D Laptop
November 12, 2004 3:00:04 AM

Archived from groups: alt.internet.wireless (More info?)

In particular, http://www.linksys.com/download/vertxt/wrt54g_ver.txt
mentions that 'Firmware 2.04.3' "Resolves issue with PPTP passthrough".
Which firmware version are you running?

"Melissa" <melissa_webster@comcast.net> wrote in message
news:b81647de.0411101717.74378136@posting.google.com...
> We have a very simple setup: Comcast Surfboard (RCA) cable modem to
> WRT54G router. 2 laptops with wireless cards (one 802.11b, the other
> 802.11g).
>
> Problem: when my husband either shuts down his laptop (with the
> 802.11g card) or disconnects his VPN tunnel without shutting down his
> laptop, my laptop loses its connection. Rebooting my PC doesn't help.
> What cures the problem (every time) is to reboot the cable modem, then
> plug the router back in. It appears that something goes wrong with IP
> addressing.
>
> From a look at the Linksys firmware download information, it doesn't
> appear this is a known/resolved problem. Could I have a problem with
> settings? Is this something I can work around? Do I have to buy an
> 802.11g card for my laptop to fix this?
>
> Thanks for any pointers!
> Melissa
!