Re: 2.6.27 seems to break something with DSL

Re: 2.6.27 seems to break something with DSL

[Marcin Slusarz]

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

Re: 2.6.27 seems to break something with DSL

[Jarek Poplawski]

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.

Re: 2.6.27 seems to break something with DSL

[Philip Stark]

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 <lcapitulino@mandriva.com.br>:
<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
>