Re: Why unidirectional ping in LAN?

In article <11ed1htgo7mfo6e@xxxxxxxxxxxxxxxxxx>, "Chris Shearer
Cooper" <chrisnews@xxxxxxx> wrote:
>My LAN looks something like this, with R1 = normal router and R2 = wireless router :
>
>Internet ----- R ----- Desktop
> 1 --+
> |
>Nothing ------ R --+
> 2 ----- Laptop
>
>The problem I'm trying to figure out, is why the laptop can ping the desktop but not vice-versa.
>
>I'm imagining the ping from the laptop hits R2 who notices the destination address is inside the subnet, so he repeats that packet on all his LAN ports, one of which is R1. R1 sees the ping, notices the destination address is inside the subnet, so he repeats the packet on all his LAN ports, one of which is the desktop.
>
>So why doesn't it work the other direction? Is the fact that the laptop is connecting wirelessly relevant somehow?
>
>Thanks!
>Chris

You don't say how you've connected the routers to each other. I'm
assuming that you've connected the WAN (Internet) port of R2 to a LAN
port of R1.

In that configuration, R2 blocks pings from the desktop to the laptop.
>From the router's point of view, the desktop is part of the Internet,
not part of the local area network, so it drops the ping request.

The laptop can ping the desktop because R2's WAN (Internet) interface
has an IP address in the same LAN as the desktop.

If you want the desktop and laptop to be in the same LAN, use R2 as a
wireless access point only, bypassing its routing capabilities:

1. Disable its DHCP server.

2. Assign its LAN interface an IP address in the same subnet that R1
uses.

3. Connect a LAN port of R2 to a LAN port of R1.

4. Don't connect anything to the WAN (Internet) port of R2.

or:

Remove R1 from the network and just use R2.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
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