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Re: [LUG] slow down?

 

Simon Robert wrote:
>
> I ran a test from speedtest.net and the only real difference was that on
> my PC the site pages loaded instantly where as on hers it took about 45
> seconds to load. Speed as mbps and ping time were pretty much identical.

This doesn't make much sense. Is this specific issue reproducible or is
it intermittent like the other issues?

Possibly it suggests an issue with something like name resolution,
although with Linux based machines I'd expect working DNS servers to be
picked up by DHCP and a working one to be preferred over any dead ones.

Similarly perhaps proxy settings in a browser, something that can
interfere with the administrative set-up of the connection but not the
performance once established.

Worth checking the settings anyway (/etc/resolv.conf and
/etc/nsswitch.conf).

Do you do any port forwarding in from the Internet?

> However a ping from the command line worked perfectly on my PC, but lost
> 26% of the packets on hers.

Ping to where?

> I changed the cable to the router and immediately all was well - for a
> few days. Now things is back the way they was. Intermittent slow downs
> and time outs.

Possibly the cable was fine but the intermittent problem went away. That
is the trouble with intermittent issues.

> I think, with no real proof, that the problem is something in the
> immediate environment.

I would run ping or similar continuously pinging the router interface to
try and rule out local networking issues. Over ethernet to local router
I'd expect 0% dropped packets, or very close to.

Worst case you can dump packets using tcpdump and analyse the period in
question, but we'll start with easier checks.

> Anyone have any ideas about what could be happening? This is driving me
> absolutely nuts. Eternal gratitude and a slug of your beverage of choice
> (even if I have to post it to you!) to anyone who can shed light on the
> problem.

Tell us more on how the routers are configured. DHCP and NAT are off on
the second router right? So it isn't doing something daft like going
over the wireless link twice on its way out.

Can you tell us the IP addresses, netmasks and routes of all the devices
involved? Can you check if their are other WiFi clients - some routers
show these. Can you check the ARP tables on the PCs normally and when
you have problems. As root "arp", or "arp -n" might be safer bet.

 Simon

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