Re: Path-MTU-discovery

[Mikael Abrahamsson <swmike () swm pp se>]

On Mon, 17 Jul 2000, Patrick W. Gilmore wrote:

> Wow, why would the ICMPs get lost?

I think it's because of access lists etc. I am not the one who have set it
up so I do not know. We've had this problem from two different companies
(one for our national needs and one for our international needs). The
international one has solved it with what you mention below.
 
> Also, cisco has a feature on tunnels now where the routers will frag & 
> de-frag making the tunnel MTU effectively 1500 bytes (or whatever you set).

Yes, this is what I have asked the people to check it out. 

>  >I do believe that NT and Win2k comes default with a registry setting that
>  >makes it send all TCP traffic with the DF flag set (which I can see no
>  >reason for unless M$ IP stack cannot do refragmentation properly). This
>  >setting is changable as far as I know but I cannot seem to find the
>  >information at this time. Anyone?
>
> I have no clue if that is really a setting.  (Do not run any MS web servers.)
>
> However, end stations do not do fragmentation.  They do re-assembly, but 
> the receiving station has no control over whether something gets fragmented 
> in transit to it.

By "refragmentation" I meant re-assembly. Sorry.

-- 
Mikael Abrahamsson    email: swmike () swm pp se