Windows can't see Apache on Linux machine when in one location, can in other. Linux PC can see server in both locations.

We have two offices A and B, connected by kilostream.

We have a Linux box in location A, running Mandrake 9 and the Apache
web server.

We have some Linux boxes in location B, and loads of Windows machines.

The problem is that whenever a Windows box is in location B, it can't
see any pages served up by the Linux based web server in A. It can
ping it, but if you telnet to port 80 from the Windows machine you get
nothing back.

If I pick up the Windows machine, and transport it to location A, plug
it into the network, all works OK.

At the moment I'm using SQUID on a Linux box in location B as a proxy
server for the Windows machines in location A, but this is a bodge
really.

Any idea why the WIndows machiens in location B can't see pages from
the apache server in A, whilst Linux machines in B can see A ?

On 8 Jul 2004 11:01:23 -0700, Agent X <(E-Mail Removed)> wrote:
> We have two offices A and B, connected by kilostream.
>
> We have a Linux box in location A, running Mandrake 9 and the Apache
> web server.
>
> We have some Linux boxes in location B, and loads of Windows machines.
>
> The problem is that whenever a Windows box is in location B, it can't
> see any pages served up by the Linux based web server in A. It can
> ping it, but if you telnet to port 80 from the Windows machine you get
> nothing back.
>
> If I pick up the Windows machine, and transport it to location A, plug
> it into the network, all works OK.
>
> At the moment I'm using SQUID on a Linux box in location B as a proxy
> server for the Windows machines in location A, but this is a bodge
> really.
>
> Any idea why the WIndows machiens in location B can't see pages from
> the apache server in A, whilst Linux machines in B can see A ?

I don't know what a kilostream is so I have no clue how you are routing
from B to A (through internet or VPN?). But Windows sometimes does some
funky routing, so it may be a routing issue.

Yesterday I was totally reinstalling Win98se on my boss' personal PC that
he was giving to his daughter. And from our company LAN, I had trouble
accessing www.adobe.com to install Acrobat reader. I noticed that adobe
had a 192... IP, and that for some reason Win98 had a local route for
192.0.0.0/255.0.0.0 (that explains it). I refreshed its DHCP IP and it
ended up with corrected 255.255.255.0 for its 192.168.x.0 network, and
then I was able to access www.adobe.com.

So run "route print" (or is it "route /print"?) on the Win boxes to see if
they have any strange routing or conflicts that may explain why B Win PCs
cannot reach server on net A.

--
David Efflandt - All spam ignored http://www.de-srv.com/

Hi,

Have you tried running tcpdump on the webserver to see if connections are
actually hitting the webserver? You mentioned it can ping but cant telnet
to port 80. From that it sounds as if routing is working. Do you have any
firewalls?

Like i mentioned, i think the best place to start would be to see if
tcpdump shows packets coming in to the webserver.

Hope that helps
Yas


On Thu, 08 Jul 2004 11:01:23 -0700, Agent X wrote:

> We have two offices A and B, connected by kilostream.
>
> We have a Linux box in location A, running Mandrake 9 and the Apache
> web server.
>
> We have some Linux boxes in location B, and loads of Windows machines.
>
> The problem is that whenever a Windows box is in location B, it can't
> see any pages served up by the Linux based web server in A. It can
> ping it, but if you telnet to port 80 from the Windows machine you get
> nothing back.
>
> If I pick up the Windows machine, and transport it to location A, plug
> it into the network, all works OK.
>
> At the moment I'm using SQUID on a Linux box in location B as a proxy
> server for the Windows machines in location A, but this is a bodge
> really.
>
> Any idea why the WIndows machiens in location B can't see pages from
> the apache server in A, whilst Linux machines in B can see A ?

I don't think it can be routing, as you can ping OK. Also the Windows
PC's have fixed IPs, though they do use WINS, whatever that is, and
don't use DNS (cos our techies don't even know what DNS is.........)

Ta, I'll check the routing. A kilostream is a 256 or 512K private
leased line between two locations, i.e. no internet or VPN involved.

please let us know what ip addressing scheme are you using for
location A and B? might be the cause that iptables has been configured
to provide access to location A.

try running ethereal to see the diagnosis messages.

raqueeb hassan
congo (drc)

> to port 80. From that it sounds as if routing is working. Do you have any
> firewalls?

No firewalls. To me the mystery is why can the Linux box on location B
see everything on the Linux box in location A fine, whilst the windows
boxes can really do nothing more than ping.

> Like i mentioned, i think the best place to start would be to see if
> tcpdump shows packets coming in to the webserver.

I've had a cursory look at tcpdump but have been been blinded by the
number of parameters on the command. What parameters do I need to pass
to it to filter only on a particular incoming IP address, and what can
I tell from the result sof the command ?

Thanks for your help.

Agent X wrote:

>> to port 80. From that it sounds as if routing is working. Do you have any
>> firewalls?
>
> No firewalls. To me the mystery is why can the Linux box on location B
> see everything on the Linux box in location A fine, whilst the windows
> boxes can really do nothing more than ping.
>
>> Like i mentioned, i think the best place to start would be to see if
>> tcpdump shows packets coming in to the webserver.
>
> I've had a cursory look at tcpdump but have been been blinded by the
> number of parameters on the command. What parameters do I need to pass
> to it to filter only on a particular incoming IP address, and what can
> I tell from the result sof the command ?
>
> Thanks for your help.
The command line string should be tcpdump host 192.xxx.xxx.xxx and
192.xxx.xxx.xxx

> please let us know what ip addressing scheme are you using for
> location A and B? might be the cause that iptables has been configured
> to provide access to location A.

It can't be an iptables thing, because:

a) its turned off
b) if you move a laptop from location B to A it works fine.


> try running ethereal to see the diagnosis messages.

I'll try that too thanks.

> The command line string should be tcpdump host 192.xxx.xxx.xxx and
> 192.xxx.xxx.xxx

ta, will try that tomorrow

> > The command line string should be tcpdump host 192.xxx.xxx.xxx and
> > 192.xxx.xxx.xxx
>

OK tried that, and saw a nice lot of output when my PC telneted or
pinged the Linux box.

Now, bizarrely, the windows box in location B showed no output when
either pinging (which worked) or telnetting (which worked) or
telnetting to the apache server on port 80 (which didn't work).

Weird.