MTU+PPP 2.4.2b3 Problem ! - PPP

This is a discussion on MTU+PPP 2.4.2b3 Problem ! - PPP ; Hi all today I installed PPP 2.4.2b3 how do I set MTU vaule to 1500 ? I added mtu 1500 to /etc/ppp/oprions still I get MTU 1492 ! thanks! Kind Regards SAber Khamooshi...

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Thread: MTU+PPP 2.4.2b3 Problem !

  1. MTU+PPP 2.4.2b3 Problem !

    Hi all
    today I installed PPP 2.4.2b3
    how do I set MTU vaule to 1500 ?
    I added mtu 1500 to /etc/ppp/oprions
    still I get MTU 1492 !

    thanks!

    Kind Regards
    SAber Khamooshi



  2. Re: MTU+PPP 2.4.2b3 Problem !

    SAber Khamooshi wrote:

    > "Clifford Kite" wrote in message
    > news:vfdqib.cl.ln@corncob.inetport.com...
    >> SAber Khamooshi wrote:
    >> > Hi all
    >> > today I installed PPP 2.4.2b3
    >> > how do I set MTU vaule to 1500 ?
    >> > I added mtu 1500 to /etc/ppp/oprions

    >> ^
    >> I'll assume this is a typo. |
    >>
    >> > still I get MTU 1492 !

    >>


    >> Are you doing PPPoE? In any case, the MTU will be changed if the other
    >> side requested a MRU of 1492. There is no way for pppd to force the
    >> peer to use a larger MRU.

    > no, I have TRANSPARENT Proxy problem .
    > when PPP 2.4.2b3 sets by default MTU 1492 or 1496, windows clients can't


    Sorry, but pppd 2.4.2.b3 doesn't set a MTU of 1492 by default. The pppd
    default MTU is 1500 and can only change if the pppd mtu option is set to a
    different value, or the peer requests a MRU smaller than 1500. Here are
    the significant PPP negotiation messages for one of my Points of Present
    using pppd 2.4.2b3 (with no explicit mtu setting):

    Using interface ppp0
    Connect: ppp0 <--> /dev/ttyS1
    sent [LCP ConfReq id=0x1 ]
    rcvd [LCP ConfAck id=0x1 ]
    rcvd [LCP ConfReq id=0x2 ]
    sent [LCP ConfAck id=0x2 ]

    The peer requested an MRU of 1524 for itself and pppd agreed. Any value
    for the MRU requested by peer that is greater than the pppd default MTU
    of 1500 is okay with pppd. In this case it will set it's MTU to 1500,
    not 1524. But if the peer requests an MRU *smaller* than 1500 then pppd
    will adjust it's MTU downward to accommodate the peer. That's true for
    *both* 2.4.1 and 2.4.2b3.

    > browse web sites. and they need to set PROXY manually to use web.
    > ( maybe stupid Windows TCP/iP )


    > I need to force MTU 1500. like PPP2.4.1 !


    Just setting the pppd mtu option to 1500 doesn't necessarily mean you'll
    get it. How do you determine what MTU pppd actually uses?

    -- Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
    PPP-Q&A links, downloads: http://ckite.no-ip.net/
    /* "PPPoE has many advantages for DSL service providers, and
    practically none for DSL consumers."
    - David F. Skoll */

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