Subject: Re: ADSL upstream problems on Sparc NetBSD 1.5
To: None <>
From: Sebastian Wain <>
List: tech-net
Date: 09/08/2001 15:30:58
On Sat, 8 Sep 2001 19:35:41 +0200
Ignatios Souvatzis <> wrote:

> On Fri, Sep 07, 2001 at 07:40:54PM -0400, Sebastian Wain wrote:
> > 
> > I played with net.ipv4.ip_no_pmtu_disc, net.inet.ip.mtudisc, 
> > net.inet.tcp_mss_ifmtu on the machine connected to the adsl modem.
> wrong machine. Let me summarize what I've read on this same mailing list,
> I think, or on news:comp.protocols.ppp
> ........
> B. Workaround: 
>    - tell the _local machine_ (NOT the PPPoE NAT gate!) to advertize a smaller
>      tcp segment size - which will make the far end of the TCP connection 
>      send smaller segments in smaller packets that aren't broken by your 
>      providers' PPPoE gete.

My Linux (for example) in my LAN has a MTU of 500, I changed it after reading some
articles on Internet.

> C. Solution: 
>    - get a real provider. Unfortunately, a lot don't care because they target
>      their PPPoE service at _single machine_ customers, who don't have the
>      problem because the PPPoE interface has a (1500 - sizeof(PPPoE header))
>      MTU, so they will automagically advertize a smaller TCP  segment size,
>      and not see big packets for the majority of applications (which are 
>      WWW over TCP, WWW over TCP, WWW over TCP, POP over TCP and SMTP over TCP).

No more providers here!!! Just one!

Thank You
Sebastian Wain