2008-10-11 12:53:28

by Philip Stark

[permalink] [raw]
Subject: 2.6.27 seems to break something with DSL

Hi,

I'm sorry, I didn't lurk before making my first posting to this list,
but it seemed to me that this might be an important problem/bug (if it
is one).

first off, my network infrastructure:

"internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
* PPPsomething i guess...

My observations so far:

with kernel =< 2.6.26 i can connect to the rest of the world perfectly
(ping works and i can browse "the internet")

now with kernel 2.6.27, i.e with all the release candidates and also
with the final version from yesterday i can ping anything just fine,
but i can't browse. that is when i 'wget kernel.org' it resolves the
address into the correct IP and then goes on to 'connecting' just to
grind to a complete halt. after some time of course it times out.
it seems to be related to the packet size because ping only seems to
work because it uses small packets. if i increase the ping size up to
1000 bytes, it fails as well. (while it does work on 2.6.26)

oh and it is the same problem on the wireless and the wired interface.
on 2 different laptops and on my desktop (which have different
networking chips, two intel and one realtek)

best Regards
Philip Stark

PS: if i horribly misposted, please slap me across the face and ignore me :)


2008-10-11 14:03:24

by Marcin Slusarz

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

On Sat, Oct 11, 2008 at 02:53:16PM +0200, Philip Stark wrote:
> Hi,
>
> I'm sorry, I didn't lurk before making my first posting to this list,
> but it seemed to me that this might be an important problem/bug (if it
> is one).
>
> first off, my network infrastructure:
>
> "internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
> * PPPsomething i guess...
>
> My observations so far:
>
> with kernel =< 2.6.26 i can connect to the rest of the world perfectly
> (ping works and i can browse "the internet")
>
> now with kernel 2.6.27, i.e with all the release candidates and also
> with the final version from yesterday i can ping anything just fine,
> but i can't browse. that is when i 'wget kernel.org' it resolves the
> address into the correct IP and then goes on to 'connecting' just to
> grind to a complete halt. after some time of course it times out.
> it seems to be related to the packet size because ping only seems to
> work because it uses small packets. if i increase the ping size up to
> 1000 bytes, it fails as well. (while it does work on 2.6.26)
>
> oh and it is the same problem on the wireless and the wired interface.
> on 2 different laptops and on my desktop (which have different
> networking chips, two intel and one realtek)
>
> best Regards
> Philip Stark
>
> PS: if i horribly misposted, please slap me across the face and ignore me :)

CC'ing netdev

2008-10-11 15:09:53

by Grant Coady

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

On Sat, 11 Oct 2008 14:53:16 +0200, "Philip Stark" <[email protected]> wrote:

>Hi,
>
>I'm sorry, I didn't lurk before making my first posting to this list,
>but it seemed to me that this might be an important problem/bug (if it
>is one).
>
>first off, my network infrastructure:
>
>"internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
>* PPPsomething i guess...

Well I connect via rp-pppoe to a bridged ADSL modem. One recent gotcha
is that iptables userspace has to be updated to match the latest kernel,
how old is your distro? What version iptables? Last I checked 1.4.1.1
was latest available from netfilter.org.

>but i can't browse. that is when i 'wget kernel.org' it resolves the
>address into the correct IP and then goes on to 'connecting' just to
>grind to a complete halt. after some time of course it times out.

This could be due to your firewall rules? More people would have
noticed if their networking died ;) (Unless you're running a e1000, all
bets off).

Grant.

2008-10-11 15:34:18

by Patrick McHardy

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

Grant Coady wrote:
> Well I connect via rp-pppoe to a bridged ADSL modem. One recent gotcha
> is that iptables userspace has to be updated to match the latest kernel,
> how old is your distro? What version iptables? Last I checked 1.4.1.1
> was latest available from netfilter.org.

No, old version should work fine, if not its a bug.

2008-10-11 15:35:43

by Philip Stark

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

2008/10/11 Grant Coady <[email protected]>:
> On Sat, 11 Oct 2008 14:53:16 +0200, "Philip Stark" <[email protected]> wrote:
>>first off, my network infrastructure:
>>
>>"internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
>>* PPPsomething i guess...
>
> Well I connect via rp-pppoe to a bridged ADSL modem.

My modem deals with all the ppp stuff and just gives out plain
LAN/ethernet/however it is called.

One recent gotcha
> is that iptables userspace has to be updated to match the latest kernel,
> how old is your distro? What version iptables? Last I checked 1.4.1.1
> was latest available from netfilter.org.

iptables: 1.4.0
distro: archlinux (rolling release) with testing repo enabled

by the way, i forgot to mention that internet works fine anywhere else
and also i can connect to a http server _inside_ my network :)

>>but i can't browse. that is when i 'wget kernel.org' it resolves the
>>address into the correct IP and then goes on to 'connecting' just to
>>grind to a complete halt. after some time of course it times out.
>
> This could be due to your firewall rules? More people would have
> noticed if their networking died ;) (Unless you're running a e1000, all
> bets off).

actually one laptop is running a e1000e... but as said, its also with
wireless...

Philip Stark

2008-10-17 08:03:45

by Jarek Poplawski

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

On 11-10-2008 16:02, Marcin Slusarz wrote:
> On Sat, Oct 11, 2008 at 02:53:16PM +0200, Philip Stark wrote:
>> Hi,
>>
>> I'm sorry, I didn't lurk before making my first posting to this list,
>> but it seemed to me that this might be an important problem/bug (if it
>> is one).
>>
>> first off, my network infrastructure:
>>
>> "internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
>> * PPPsomething i guess...
>>
>> My observations so far:
>>
>> with kernel =< 2.6.26 i can connect to the rest of the world perfectly
>> (ping works and i can browse "the internet")
>>
>> now with kernel 2.6.27, i.e with all the release candidates and also
>> with the final version from yesterday i can ping anything just fine,
>> but i can't browse. that is when i 'wget kernel.org' it resolves the
>> address into the correct IP and then goes on to 'connecting' just to
>> grind to a complete halt. after some time of course it times out.
>> it seems to be related to the packet size because ping only seems to
>> work because it uses small packets. if i increase the ping size up to
>> 1000 bytes, it fails as well. (while it does work on 2.6.26)
>>
>> oh and it is the same problem on the wireless and the wired interface.
>> on 2 different laptops and on my desktop (which have different
>> networking chips, two intel and one realtek)
>>
>> best Regards
>> Philip Stark
>>
>> PS: if i horribly misposted, please slap me across the face and ignore me :)

Hi,

Could you send tcpdump -v on some interface as near "internet" as
possible while doing this 1000 bytes ping? (Btw. what is this router?)
It would be nice to have this both for 2.6.26 and 2.6.27.

Thanks,
Jarek P.

Subject: Re: 2.6.27 seems to break something with DSL

Em Sat, 11 Oct 2008 14:53:16 +0200
"Philip Stark" <[email protected]> escreveu:

| I'm sorry, I didn't lurk before making my first posting to this list,
| but it seemed to me that this might be an important problem/bug (if it
| is one).
|
| first off, my network infrastructure:
|
| "internet" --(magic*)-- DSL Modem --(DHCP)-- Router --(DHCP)-- Computer
| * PPPsomething i guess...
|
| My observations so far:
|
| with kernel =< 2.6.26 i can connect to the rest of the world perfectly
| (ping works and i can browse "the internet")
|
| now with kernel 2.6.27, i.e with all the release candidates and also
| with the final version from yesterday i can ping anything just fine,
| but i can't browse. that is when i 'wget kernel.org' it resolves the
| address into the correct IP and then goes on to 'connecting' just to
| grind to a complete halt. after some time of course it times out.
| it seems to be related to the packet size because ping only seems to
| work because it uses small packets. if i increase the ping size up to
| 1000 bytes, it fails as well. (while it does work on 2.6.26)

If you haven't solved this issue yet you could try:

# echo 0 > /proc/sys/net/ipv4/tcp_timestamps

We (Mandriva) have had some reports of this issue and it seems that
some broken routers can drop packages because of the timestamp (that's
what our local network guy has said). Disabling timestamps make it work
again.

--
Luiz Fernando N. Capitulino

2008-10-21 22:28:56

by Philip Stark

[permalink] [raw]
Subject: Re: 2.6.27 seems to break something with DSL

I was just going to say that Bug Nr. 11721 on bugzilla.kernel.org is
exactly my problem and is in fact resolved with the
solution/workaround presented there.

Thanks for your time
Philip Stark

2008/10/20 Luiz Fernando N. Capitulino <[email protected]>:
<snip>
> | it seems to be related to the packet size because ping only seems to
> | work because it uses small packets. if i increase the ping size up to
> | 1000 bytes, it fails as well. (while it does work on 2.6.26)
>
> If you haven't solved this issue yet you could try:
>
> # echo 0 > /proc/sys/net/ipv4/tcp_timestamps
>
> We (Mandriva) have had some reports of this issue and it seems that
> some broken routers can drop packages because of the timestamp (that's
> what our local network guy has said). Disabling timestamps make it work
> again.
>
> --
> Luiz Fernando N. Capitulino
>