Strange Network Behaviour - Next Installment

This is to keep informed Bit Twister and others who were following the
previous thread. To recap:

LAN -> switch-> linux gateway/router -> DMZ -> ADSL2-modem/router

Hosts on the lan sometimes cannot see the gateway and beyond.


Rather than try to quantify the throughput of the linux gateway box, I
replaced it with something with considerable more grunt. I ended up using
a Celery 3 GHz machine, and still had the problems. So I'm pretty sure
that it's not a throughput problem, although it never really looked
like one anyway. I can see throughput slowing the network down, but not
making the gateway invisible.

So the problem appears to be the switch, but this was the first thing I
replaced ages ago.

So now I've added a second gateway box and routed everything from
downstairs through it. Upstairs and downstairs are now effectively
isolated. Both their gateways go onto the dmz and from there out to the
internet. I've got my ping diagnostics that Bit Twister recommended
running on boxes on both parts of the network. Now to see if, when, and
where errors occur.

Dan

"Dan N" <(E-Mail Removed)> wrote in message
news(E-Mail Removed) ldomain

> This is to keep informed Bit Twister and others who were following the
> previous thread.

Too bad you started a new thread, as the historical connection will be lost
to those who need it in the future.

On Wed, 10 May 2006 15:20:50 +0800, Dan N wrote:

> This is to keep informed Bit Twister and others who were following the
> previous thread.

I was wondering if I had somehow missed a post or two...

> Rather than try to quantify the throughput of the linux gateway box, I
> replaced it with something with considerable more grunt. I ended up using
> a Celery 3 GHz machine, and still had the problems. So I'm pretty sure
> that it's not a throughput problem, although it never really looked
> like one anyway.
> I can see throughput slowing the network down, but not
> making the gateway invisible.

I thought so also. I had seen someone mention a 10mb nic could be kept
maxed out with an old pokey 486 a few years ago.

Your system should have been able to keep up due to throttling at the
internet connection.

The only thing I could dream up would be a lan side gateway firewall thinking
it need to throttle inbound. I just would not believe it.


> So the problem appears to be the switch, but this was the first thing I
> replaced ages ago.

I was guessing the switch, but as a victim, the culprit being the doze
boxes beating up the network causing collisions. That still did not
make sense because I would think pings should still get through.

> So now I've added a second gateway box and routed everything from
> downstairs through it. Upstairs and downstairs are now effectively
> isolated.

Well that knocks off the load/collisions at the switch.

Upside is you can stop the ping test and watch the tx/x counts on each
lan gateway nic and see if you have very high traffic conditions.

On Wed, 10 May 2006 00:28:38 -0700, ynotssor wrote:

> Too bad you started a new thread, as the historical connection will be
> lost to those who need it in the future.

The alternative was to use an old thread that might have gone out of view.

Dan

On Wed, 10 May 2006 03:28:29 -0500, Bit Twister wrote:

>> So the problem appears to be the switch, but this was the first thing I
>> replaced ages ago.
>
> I was guessing the switch, but as a victim, the culprit being the doze
> boxes beating up the network causing collisions. That still did not make
> sense because I would think pings should still get through.

None of it makes any real sense. I'm thinking there might be some kind of
hardware issue. I want to say something like different earth levels, but
ethernet is differential signals not referenced to ground, so that can't
be right. But something along those lines. It can be solid for a couple
of days, then have ping errors every five minutes all day. And sometimes
it looks like it's related to the hours when there's more traffic, but
other times it happens in the middle of the night.

Since I've separated the network, each with its own gateway, it's been
solid. But I need to watch it at least a couple of days.

Dan

"Dan N" <(E-Mail Removed)> wrote in message
news(E-Mail Removed) ldomain

>> Too bad you started a new thread, as the historical connection will
>> be lost to those who need it in the future.
>
> The alternative was to use an old thread that might have gone out of
> view.

What does "gone out of view" mean?

On Wed, 10 May 2006 12:27:28 -0700, ynotssor wrote:


> What does "gone out of view" mean?

Means you can't see it anymore because new posts push it down the list.
Means it can go unnoticed.

On Wed, 10 May 2006 15:20:50 +0800, Dan N wrote:

Here's the latest. Upstairs shows no ping errors. Downstairs is pinging
its gateway plus hosts in the dmz. All is well, except that it's missing
the odd ping to the mail server in the dmz, which is a bit odd. Before I
installed the second gateway, ping errors occurred to the gateway. Now
they're occurring with only one host in the dmz.

Dan



> This is to keep informed Bit Twister and others who were following the
> previous thread. To recap:
>
> LAN -> switch-> linux gateway/router -> DMZ -> ADSL2-modem/router
>
> Hosts on the lan sometimes cannot see the gateway and beyond.
>
>
> Rather than try to quantify the throughput of the linux gateway box, I
> replaced it with something with considerable more grunt. I ended up using
> a Celery 3 GHz machine, and still had the problems. So I'm pretty sure
> that it's not a throughput problem, although it never really looked like
> one anyway. I can see throughput slowing the network down, but not making
> the gateway invisible.
>
> So the problem appears to be the switch, but this was the first thing I
> replaced ages ago.
>
> So now I've added a second gateway box and routed everything from
> downstairs through it. Upstairs and downstairs are now effectively
> isolated. Both their gateways go onto the dmz and from there out to the
> internet. I've got my ping diagnostics that Bit Twister recommended
> running on boxes on both parts of the network. Now to see if, when, and
> where errors occur.
>
> Dan

On Thu, 11 May 2006 10:40:57 +0800, Dan N wrote:
> On Wed, 10 May 2006 15:20:50 +0800, Dan N wrote:
>
> Here's the latest. Upstairs shows no ping errors. Downstairs is pinging
> its gateway plus hosts in the dmz. All is well, except that it's missing
> the odd ping to the mail server in the dmz, which is a bit odd. Before I
> installed the second gateway, ping errors occurred to the gateway. Now
> they're occurring with only one host in the dmz.

Rule out the switch by swapping up upstair switch with downstair switch.
Or gateway box whichever is common.
No change, swap downstair lan boxes with upstairs lan boxes.

"Dan N" <(E-Mail Removed)> wrote in message
news(E-Mail Removed) ldomain

>> What does "gone out of view" mean?
>
> Means you can't see it anymore because new posts push it down the
> list. Means it can go unnoticed.

How absurd ... learn to take control of your Pan newsreader:

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