LAN or provider problem?

Hi,
i have a small networking problem. A debian server connects the LAN to
the internet, does the routing, DNS and proxy. Almost everything works
fine - but i can´t access two or three sites, not a bit. Most probably
there are more sites unaccessible which i just don´t know, but
www.ebay.de is definitely unreachable. Ping packet loss is 100%,
traceroute gets lost after 3 hops without error. Is this rather a
routing problem of the provider or something i screwed up?
Any hints?

timbo
--
Reply to: tim at boneko dot de

Tim Boneko wrote:

> Hi,
> i have a small networking problem. A debian server connects the LAN to
> the internet, does the routing, DNS and proxy. Almost everything works
> fine - but i can´t access two or three sites, not a bit. Most probably
> there are more sites unaccessible which i just don´t know, but
> www.ebay.de is definitely unreachable. Ping packet loss is 100%,
> traceroute gets lost after 3 hops without error. Is this rather a
> routing problem of the provider or something i screwed up?
> Any hints?

It's probably a routing problem somewhere, but just to be sure, try
connecting another computer directly to your internet connection and see
what happens.

FWIW, I can't traceroute to it either.

"Tim Boneko" schrieb
> Hi,
> i have a small networking problem. A debian server connects the
LAN to
> the internet, does the routing, DNS and proxy. Almost everything
works
> fine - but i can´t access two or three sites, not a bit. Most
probably
> there are more sites unaccessible which i just don´t know, but
> www.ebay.de is definitely unreachable. Ping packet loss is 100%,
> traceroute gets lost after 3 hops without error. Is this rather a
> routing problem of the provider or something i screwed up?
> Any hints?
>
While the article
http://portal.suse.com/sdb/en/2001/11/cg_internet.html
strictly only applies to SUSE (especially in the configuration files
that have
to be tweaked), it may help you.

HTH
Martin

Tim Boneko schreef:
> Hi,
> i have a small networking problem. A debian server connects the LAN to
> the internet, does the routing, DNS and proxy. Almost everything works
> fine - but i can´t access two or three sites, not a bit. Most probably
> there are more sites unaccessible which i just don´t know, but
> www.ebay.de is definitely unreachable. Ping packet loss is 100%,
> traceroute gets lost after 3 hops without error. Is this rather a
> routing problem of the provider or something i screwed up?
> Any hints?
>
> timbo

I can't ping nor traceroute www.ebay.de either, but accessing it on port
80 works and also in a browser. What is the address you get from your
DNS? I get 66.135.208.95 (hp-intl-de.ebay.com).

--
Max

Open Source is an ode to common sense

Max schrieb:

> I can't ping nor traceroute www.ebay.de either, but accessing it on port
> 80 works and also in a browser. What is the address you get from your
> DNS? I get 66.135.208.95 (hp-intl-de.ebay.com).

Same address, but no ping, no data at all.
I connected another computer to the link as James Knott suggested, no
problems with any site. I don´t know where to start digging now!
Does anyone have an idea?

timbo
--
Reply to tim at boneko dot de

Tim Boneko wrote:
> Max schrieb:
>
>
>>I can't ping nor traceroute www.ebay.de either, but accessing it on port
>>80 works and also in a browser. What is the address you get from your
>>DNS? I get 66.135.208.95 (hp-intl-de.ebay.com).
>
>
> Same address, but no ping, no data at all.
> I connected another computer to the link as James Knott suggested, no
> problems with any site. I don´t know where to start digging now!
> Does anyone have an idea?

Try reducing the MTU value of your WAN facing interface. It sounds like
your box is attempting MTU discovery but the ebay site is not sending
back the ICMP responses required to make it work. It's actually a
misconfiguration on the there side not yours.

Thanks
Mark

Hi Mark,

Mark Broadbent schrieb:

> Try reducing the MTU value of your WAN facing interface. It sounds like

That was actually the problem. I had heard of that mtu setting problem
and reduced the mtu to 1420 (don´t know why that low...)
Resetting it to 1492 fixed the problem. BTW, www.postbank.de was also
affected.

Thanks to you all!

timbo
--
Reply to tim at boneko dot de

> Mark Broadbent schrieb:
>
>
>>Try reducing the MTU value of your WAN facing interface. It sounds like
>
Tim Boneko wrote:
> Hi Mark,
>
>
> That was actually the problem. I had heard of that mtu setting problem
> and reduced the mtu to 1420 (don´t know why that low...)
> Resetting it to 1492 fixed the problem. BTW, www.postbank.de was also
> affected.

There may ba a firewall eating all ICMP messages on the way.

Please check yours that the 'Fragmentation needed, but
DF bit set' ICMP messages are not blocked.

--

Tauno Voipio
tauno voipio (at) iki fi

"Tim Boneko" <(E-Mail Removed)> wrote in message
news:430b2154$0$2119$(E-Mail Removed)...

> Hi Mark,
>
> Mark Broadbent schrieb:
>
>> Try reducing the MTU value of your WAN facing interface. It sounds like
>
> That was actually the problem. I had heard of that mtu setting problem
> and reduced the mtu to 1420 (don´t know why that low...)
> Resetting it to 1492 fixed the problem. BTW, www.postbank.de was also
> affected.
>
> Thanks to you all!

The problem is almost definitely some idiot with a misconfigured
firewall. ICMP is an Internet host requirement, it is not optional.

Check to make sure the idiot isn't you.

DS

David Schwartz schrieb:

> Check to make sure the idiot isn't you.

Wouldn't be the first time...
Thx,

timbo
--
Reply to: tim at boneko dot de