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RE: My ADSL saga - Updates



Hello,
As far as I understand, changing MTU on a router should not prevent
clients with higher MTU working. I mean that if some router receives
packet it cannot pass as-is, it should return some kind of ICMP error,
and the client should re-send the packet with smaller MTU. So if it's
true and the problem is with MTU on Netvision router, then either the
router is misconfigured, or incoming icmp is incorrectly blocked with
firewall rules on client.

Other (but close) topic:
ADSL connection can be described as high-bandwidth high-latency (to U.S.
networks at least), therefore transfer times can be improved greatly
with larger TCP receive window. I saw that changing RWIN on Windows can
gain 30% in download speeds with ADSL. Anybody knows if receive window
is worth tweaking on Linux, and if yes, how to do it correctly. I took a
look at kernel documentation, and then in the /proc, but there are too
many parameters there, and I cannot see any apparent results by changing
them. I'm using 2.4.5 kernel.

Haim Gelfenbeyn.


> -----Original Message-----
> From: linux-il-bounce@cs.huji.ac.il 
> [mailto:linux-il-bounce@cs.huji.ac.il] On Behalf Of Dani Arbel
> Sent: Thursday, July 05, 2001 3:14 PM
> To: Hetz Ben Hamo
> Cc: ILUG
> Subject: Re: My ADSL saga - Updates
> 
> 
> Hetz,
> any idea WHY they did it? Is it just to break the 
> masquerading setup, or
> is there some technical reason (say, if they do a tunnel 
> inside a tunnel
> ..).
> Cause if they did it just because, next they will reduce 
> another 20 bytes
> of the MTU ...
> Dani
> 
> On Thu, 5 Jul 2001, Hetz Ben Hamo wrote:
> 
> > Hi All,
> >
> > Well, my good friend Andrei and I sat on my machines and 
> decided that will
> > solve this issue - no matter what the costs ;)
> >
> > So we found out...
> >
> > 1. Netivision changed the MTU to 1424 - anyone got an email 
> notification
> > about this? cause I didn't..
> >
> > 2. My firewall is based still on kernel 2.2.x - meaning - 
> it won't fix the
> > mtu bug which was fixed on kernel 2.4.x - thats why my 
> Linux workstation had
> > those problems..
> >
> > So - if you are connected to Netvision - set your ADSL 
> firewall to MTU 1424.
> > Is it based on kernel 2.2.x? then either upgrade it to 
> 2.4.6 (which came out
> > today) or do the more pain way - update all machines behind 
> it to mtu 1424 on
> > their ethernet...
> >
> > Fun Fun Fun....
> >
> > Hetz
> >
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> >
> 
> 
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