No ping, Wifi ?

I have just got the following set up and working, all on the same IP
range and all given fixed IP's.

Phone line, to wireless router1, then via cat5 to wireless router2.

Router2 then connects to a yagi to provide a 0.5km link to PC2.

PC1 connects to router1 by wifi over a short distance.

Using Freeping, PC1 can successfully ping either router, various other
items on my LAN and on the WAN, except PC2 which never responds.

Not sure, but the (inexperienced) person using PC2 thinks he can
successfully ping PC1.

The question is why can't I ping PC2 from PC1?

The 0.5km link BTW, works very well indeed using home built yagi
antennas, rock solid despite there being very many local access points
along the route of the link.


--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article <(E-Mail Removed)> , Harry
Bloomfield <(E-Mail Removed)> wrote:

> I have just got the following set up and working, all on the same IP
> range and all given fixed IP's.
>
> Phone line, to wireless router1, then via cat5 to wireless router2.
>
> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>
> PC1 connects to router1 by wifi over a short distance.
>
> Using Freeping, PC1 can successfully ping either router, various other
> items on my LAN and on the WAN, except PC2 which never responds.
>
> Not sure, but the (inexperienced) person using PC2 thinks he can
> successfully ping PC1.
>
> The question is why can't I ping PC2 from PC1?
>
> The 0.5km link BTW, works very well indeed using home built yagi
> antennas, rock solid despite there being very many local access points
> along the route of the link

Is it too obvious to ask if PC2 is configured to ignore ping (ICMP
echo) packets? Check its firewall settings.

Just a thought :-)

Bob Jones

--
Robert S. Jones, I.T. Security Consultant | Vox +44 20 7882 5326
Computing Services, Mile End Campus | Fax +44 20 8980 2001
Queen Mary, University of London, U.K. | GSM +44 79 56 383659

Harry Bloomfield wrote:
> I have just got the following set up and working, all on the same IP
> range and all given fixed IP's.
>
> Phone line, to wireless router1, then via cat5 to wireless router2.
>
> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>
> PC1 connects to router1 by wifi over a short distance.
>
> Using Freeping, PC1 can successfully ping either router, various other
> items on my LAN and on the WAN, except PC2 which never responds.
>
> Not sure, but the (inexperienced) person using PC2 thinks he can
> successfully ping PC1.
>
> The question is why can't I ping PC2 from PC1?
>
> The 0.5km link BTW, works very well indeed using home built yagi
> antennas, rock solid despite there being very many local access points
> along the route of the link.
>
>
What IP addresees are on the kit and is the Wifi set up to actually be
routable, or is it all a bridged network..?

"Harry Bloomfield" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) k...
>I have just got the following set up and working, all on the same IP range
>and all given fixed IP's.
>
> Phone line, to wireless router1, then via cat5 to wireless router2.
>
> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>
> PC1 connects to router1 by wifi over a short distance.
>
> Using Freeping, PC1 can successfully ping either router, various other
> items on my LAN and on the WAN, except PC2 which never responds.
>
> Not sure, but the (inexperienced) person using PC2 thinks he can
> successfully ping PC1.
>
> The question is why can't I ping PC2 from PC1?
>
> The 0.5km link BTW, works very well indeed using home built yagi antennas,
> rock solid despite there being very many local access points along the
> route of the link.

In this configuration, wireless router2 should be configured as a Wireless
Access Point. Specifically, this means that its DHCP service is disabled,
and the cat5 feed into the device should be plugged into a LAN connection
rather than a WAN connection. It would be helpful here to know the make &
model number of Router2, because some types do not bridge traffic between
the wired and wireless LAN ports.

(Note that is would be possible to have Router2 remain configured as a
router. But this would mean that all the devices connected to its LAN
[either wired or wireless] would be hidden behind NAT.)

First disconnect router2 from everything. Then connect a computer to it
(via a cat5 cable), and reconfigure the router for a static IP address in
the same subnet as Router1, but outside the DHCP scope of Router1. Make a
note of the IP address you chose. Now disable the DHCP service in Router2.

Reconnect Router2 using the cat5 cable to Router1. Connect PC1 to Router1.

Can PC1 ping Router1? You've not changed anything that would affect this,
so if this doesn't work you have to start from scratch - ask for more help.
Bear in mind that ping is built in to all PCs (since Windows 3.1). Note
that IPCONFIG /ALL is also useful.

Can PC1 ping Router2?

[What is your reason for having static IP addresses on the PCs? Better to
use the "auto" setting unless you need to publish resources - even then, a
pseudo-static setting achieved in Router1 by binding IP to MAC address would
be better - but some routers can't do this.]

Connect PC3 using cat5 cable to Router2. (If you don't have a spare PC then
re-deploy PC1. Note that some routers and switches keep IP-MAC associations
in an ARP cache for inconveniently long times - if necessary reboot the
routers.) This should get an IP address from the DHCP server in Router1.
Can PC3 ping Router1? Can it ping Router2? Can it ping PC1? Can PC1 ping
PC3? All these pings should succeed. If any fail, investigate firewall
settings on the PCs, and if necessary report back.

Now go the remote site where PC2 is located, and see for yourself how it is
set up. How does PC2 get the wireless signal? Is it a built-in wireless
adapter, or a separate wireless access point? Does it show good wireless
signal strength? Have you configured the correct security for the link to
Router2? Does PC2 get an IP address when you set it to "auto"? (This will
come from Router1, and Router1 might show what IP address has been issued.)
Can PC2 ping both the routers?

How is the firewall configured on PC2? Bring PC2 to the home site and
connect it by wire to Router1 - can you now ping it from PC1?

--
Graham J

Robert Jones explained on 25/02/2009 :
> In article <(E-Mail Removed)> , Harry
> Bloomfield <(E-Mail Removed)> wrote:
>
>> I have just got the following set up and working, all on the same IP
>> range and all given fixed IP's.
>>
>> Phone line, to wireless router1, then via cat5 to wireless router2.
>>
>> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>>
>> PC1 connects to router1 by wifi over a short distance.
>>
>> Using Freeping, PC1 can successfully ping either router, various other
>> items on my LAN and on the WAN, except PC2 which never responds.
>>
>> Not sure, but the (inexperienced) person using PC2 thinks he can
>> successfully ping PC1.
>>
>> The question is why can't I ping PC2 from PC1?
>>
>> The 0.5km link BTW, works very well indeed using home built yagi
>> antennas, rock solid despite there being very many local access points
>> along the route of the link
>
> Is it too obvious to ask if PC2 is configured to ignore ping (ICMP
> echo) packets? Check its firewall settings.

It is set up on WinXP's default, just as it comes out the box. Would
the XP firewall ignore the ping requests on its default settings?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

The Natural Philosopher expressed precisely :
> Harry Bloomfield wrote:
>> I have just got the following set up and working, all on the same IP range
>> and all given fixed IP's.
>>
>> Phone line, to wireless router1, then via cat5 to wireless router2.
>>
>> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>>
>> PC1 connects to router1 by wifi over a short distance.
>>
>> Using Freeping, PC1 can successfully ping either router, various other
>> items on my LAN and on the WAN, except PC2 which never responds.
>>
>> Not sure, but the (inexperienced) person using PC2 thinks he can
>> successfully ping PC1.
>>
>> The question is why can't I ping PC2 from PC1?
>>
>> The 0.5km link BTW, works very well indeed using home built yagi antennas,
>> rock solid despite there being very many local access points along the
>> route of the link.
>>
>>
> What IP addresees are on the kit and is the Wifi set up to actually be
> routable, or is it all a bridged network..?

Sorry I don't know the answer, Router2 is just and old Belkin 11Mb
wifi, with a WAN port (not connected) and 4 LAN ports. One of the later
ports is used to connect to router1.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Graham J has brought this to us :
> In this configuration, wireless router2 should be configured as a Wireless
> Access Point. Specifically, this means that its DHCP service is disabled,
> and the cat5 feed into the device should be plugged into a LAN connection
> rather than a WAN connection. It would be helpful here to know the make &
> model number of Router2, because some types do not bridge traffic between the
> wired and wireless LAN ports.

That has all been done. It is an old (expendable) Belkin 11Mb wifi unit
F5D6230-2. I cannot actually get to the router, it is mounted atop a
pole 30 feet up in a waterproof box :-)

I noted something else after posting, which might or might not mean
something....

If I check router2's status page, there is a line which reads
'Connected Clients' - this reads zero even when PC2 is connected and
using the Internet. Not sure whether the number might include wifi
connected clients, or just wired LAN clients.

>
> (Note that is would be possible to have Router2 remain configured as a
> router. But this would mean that all the devices connected to its LAN
> [either wired or wireless] would be hidden behind NAT.)

NAT is presently enabled on router2, should I disable it?

> First disconnect router2 from everything. Then connect a computer to it (via
> a cat5 cable), and reconfigure the router for a static IP address in the same
> subnet as Router1, but outside the DHCP scope of Router1. Make a note of the
> IP address you chose. Now disable the DHCP service in Router2.

All of that has already been done prior to fixing it outside, but
obviously I can access the setup page from my PC.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 2009-02-24, Harry Bloomfield <(E-Mail Removed)> wrote:
> Using Freeping, PC1 can successfully ping either router, various other
> items on my LAN and on the WAN, except PC2 which never responds.
>
> Not sure, but the (inexperienced) person using PC2 thinks he can
> successfully ping PC1.
>
> The question is why can't I ping PC2 from PC1?

Did the (inexperienced) person using PC2 also configure it? Maybe the
static address he configured isn't what you though he set it to.

To debug this from your end you might try pinging the subnet
broadcast address to see if any unknown addresses show up. Also,
if PC1 were a Unix box I'd suggest running tcpdump on it and watching
what arrives when PC2 is supposed to be successfully pinging PC1,
though I don't know what the windows equivalent of this would be.

Dennis Ferguson

On Thu, 26 Feb 2009 07:06:25 UTC, Dennis Ferguson
<(E-Mail Removed)> wrote:

I think ping response is off by default on Win. boxes.

> To debug this from your end you might try pinging the subnet
> broadcast address to see if any unknown addresses show up.

<snip>

> Dennis Ferguson

Thank you Dennis, one learns something new every day :-) Been messing
with networks for years and I never knew that!

--
Regards
Dave Saville

NB Remove nospam. for good email address

"Harry Bloomfield" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) k...
> Robert Jones explained on 25/02/2009 :
>> In article <(E-Mail Removed)> , Harry
>> Bloomfield <(E-Mail Removed)> wrote:
>>
>>> I have just got the following set up and working, all on the same IP
>>> range and all given fixed IP's.
>>>
>>> Phone line, to wireless router1, then via cat5 to wireless router2.
>>>
>>> Router2 then connects to a yagi to provide a 0.5km link to PC2.
>>>
>>> PC1 connects to router1 by wifi over a short distance.
>>>
>>> Using Freeping, PC1 can successfully ping either router, various other
>>> items on my LAN and on the WAN, except PC2 which never responds.
>>>
>>> Not sure, but the (inexperienced) person using PC2 thinks he can
>>> successfully ping PC1.
>>>
>>> The question is why can't I ping PC2 from PC1?
>>>
>>> The 0.5km link BTW, works very well indeed using home built yagi
>>> antennas, rock solid despite there being very many local access points
>>> along the route of the link
>>
>> Is it too obvious to ask if PC2 is configured to ignore ping (ICMP
>> echo) packets? Check its firewall settings.
>
> It is set up on WinXP's default, just as it comes out the box. Would the
> XP firewall ignore the ping requests on its default settings?

My recollection is that you have to enable file sharing before you can ping
into the PC.

--
Graham J