Re: [Openvpn-users] path-mtu 1460 : message too long

[richard <rvenne@xxxxxxxxxxxxxxxxx>]

yeah sure,I agree.
which means:
a routing table had been changed, (ospf, bgb who knows), and my packets 
are too long for one of them, which make those errors. so, how can I 
guesse the right mtu value in order to be sure, that my packets could 
pass through the isp's equipments? should I try about a lot of mtu 
values?each of my vpn clients could have a diffrent isp with diffrent 
wan link:

(x)dsl, satelite, isdn, wifi, radio,frame relay..........and they could 
be in diffrent countries.so, I figure that (mtu error) may happen...
so my question is:

why my mtu errors were only visible in openvpn console? they may be a 
copy of 4th(tcp/udp)layer error message. why don't the mtu-discovry 
mechanisme do its job, in order to adjust?does openvpn have its own 
mtu-discovry mechanisme inside the tunnels?
James Yonan wrote:
> On Mon, 3 Jan 2005, richard wrote:
>
>
> > aah, thanks a lot, that works well
> >
> > but why is it necessary? that worked well before until last week.
>
>
> Here's a metaphor.  Suppose you are driving a truck (lorry) across your 
> country and it's 5 metres tall.  Now a natural disaster occurs and the 
> roads which you usually drive on are closed, forcing you to detour onto 
> smaller roads which have lower bridges and tunnels.  Maybe some of the 
> tunnels give you less than 5 metres of safe clearance!
>
> In this metaphor each internet router is like a bridge or tunnel which 
> constrains the height of your vehicle, i.e. the packet size.
>
> Using an mssfix value of 1200 is sort of like using a truck that's only 4 
> metres tall instead of 5.  You can't carry as much payload, so it's less 
> efficient, but at least you know that you will get through.
>
> James
>
>
> > James Yonan wrote:
> >
> > > On Fri, 31 Dec 2004, richard wrote:
> > >
> > >
> > >
> > > > I get this openvpn(beta 15) error message when I put in "ls /etc/", or 
> > > > "less $A_BIG_PLAIN_TEXT_FILE". my session freeze and the only way to get 
> > > > it back is killing the ssh process (openvpn still running).
> > > >
> > > >
> > > > linux client------->fbsd server--------->linux client
> > >
> > >
> > > Try "mssfix 1200".
> > >
> > > James
> > >
> > >
> > >
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