PPTP MTU

Michael Bretterklieber mbretter at a-quadrat.at
Sun Mar 28 23:18:54 PST 2004


Hi,

On Sun, 28 Mar 2004, Jay Hall wrote:
> OK, I think I have an MTU negotiation problem.  The server side sets an
> MTU of 1458 and the client side sets an MTU of 1456.  Occassionally, the
> MTUs on the client and the server will be the same and then the
> connection comes up and runs like a champ as long as the MTU is 1456.
> Any other values, even if they are the same on the client and server end
> result in a connection that comes up and then drops.
>
> Both the client and the server contain the line
>
> set link mtu 1460
>
> Mar 27 00:22:52 ST_CHARLES mpd: [vpn] CCP: rec'd Configure Nak #1 link 0
> (Req-Sent)
> Mar 27 00:22:52 ST_CHARLES mpd:  MPPC
> Mar 27 00:22:52 ST_CHARLES mpd:    0x01000040: MPPE, 128 bit, stateless
> Mar 27 00:22:52 ST_CHARLES mpd: [vpn] CCP: SendConfigReq #2
> Mar 27 00:22:52 ST_CHARLES mpd:  MPPC
> Mar 27 00:22:52 ST_CHARLES mpd:    0x01000040: MPPE, 128 bit, stateless
> Mar 27 00:22:52 ST_CHARLES mpd: [vpn] error writing len 14 frame to
> bypass: No route to host

there is a problem with the underlaying connection, could you please post
the whole log, from the beginning of the connection.

the value of 1456 is ok, because Mpd takes the ppp-header into account,
wich has usually 4 bytes.

bye,
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Michael Bretterklieber          - http://www.bretterklieber.com
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