Os9 Mtu

Discussion in 'Mac Apps and Mac App Store' started by damage, Mar 4, 2003.

  1. damage macrumors newbie

    Joined:
    Feb 17, 2003
    Location:
    Sydney, Australia
    #1
    Can anyone tell me how..if at all I can change my mtu setting in os9 ?

    Please :)
     
  2. Jaykay macrumors 6502a

    Jaykay

    Joined:
    Dec 1, 2002
    Location:
    Ireland
  3. TMA macrumors 6502a

    TMA

    Joined:
    Jan 6, 2003
    Location:
    England
    #3
  4. Jaykay macrumors 6502a

    Jaykay

    Joined:
    Dec 1, 2002
    Location:
    Ireland
    #4
    Ah, now i know what that is. (sometimes people should'nt do that to phrases.....)
     
  5. Jaykay macrumors 6502a

    Jaykay

    Joined:
    Dec 1, 2002
    Location:
    Ireland
    #5
    Yeah, i used tha program a good while back and it does let you adjust the (ugghhhh) TMU among other things, works a treat. Dont use it now cos im usin OS X.
     
  6. damage thread starter macrumors newbie

    Joined:
    Feb 17, 2003
    Location:
    Sydney, Australia
    #6
    Cheers for the answer...yeah I'm an OSX user as well but I have a client who refuses to leave os9 due to some of their apps wich don't function properly under classic mode.

    I'll give it a try.
     
  7. damage thread starter macrumors newbie

    Joined:
    Feb 17, 2003
    Location:
    Sydney, Australia
    #7
    is there any chance there is a shareware package that will do the same thing ?

    or is it possible to do without 3rd party software ?

    Thanks in Advance :)
     
  8. evoluzione macrumors 68020

    evoluzione

    Joined:
    Jul 19, 2002
    Location:
    down the road, that's where i'll always be
    #8
    so is this something that allows you to control the bandwidth of users logging onto your server for example???
     
  9. damage thread starter macrumors newbie

    Joined:
    Feb 17, 2003
    Location:
    Sydney, Australia
    #9
    Here's a bit more info that I found

    On my OS9.2.1 Installer CD there is an optional control panel (drag & drop into the system folder) called "TCP/IP Options" located in

    mac OS9.2.1:CD Extras:Network Extras:OTExtras:TCP/IP:

    Here's the start of what the Readme has to say:

    IMPORTANT Do not use the TCP/IP Options control panel (previously called TCP/IP Path Discovery Control control panel) unless instructed to do so by your network administrator. TCP/IP Options is an unsupported utility developed by Apple Computer, Inc. It allows you to modify Open Transport/TCP's default behavior to disable the ?Path MTU Discovery? feature and provide compatibility with certain third-party applications. (The one most commonly encountered is ATEX's MacText, a software terminal emulator for the ATEX/SysDeco Standard/Advanced Display Terminal.)

    About the Path MTU Discovery feature

    Path MTU Discovery is an Internet standard implemented and automatically enabled in Open Transport/TCP. (This standard is not implemented in MacTCP.) Here?s how it works:

    ? Unless a packet size is larger than the MTU for a network, Open Transport/TCP sets the ?don?t fragment? bit in an IP datagram header on transmission.

    ? When presented with a ?don?t fragment? packet that cannot be forwarded without fragmentation with the MTU size, intermediate routers send back an ?ICMP can't fragment? error (required by current RFCs).

    ? When an ?ICMP can't fragment? error is sent back, Open Transport/TCP moves to the next smaller MTU size for that path, sets the ?don?t fragment? bit, and re-sends the packet. This process automatically results in using the largest supported MTU size for off-subnet traffic.

    The standards document that describes Path MTU Discovery is available on the Internet at ds.internic.net/rfc/rfc1191.txt.

    Why disable the Path MTU Discovery feature?

    Path MTU Discovery works by sending datagrams with the ?don?t fragment? bit set. Some older routers don't handle this bit properly. Disabling Path MTU Discovery prevents the use of the ?don?t fragment? bit and may allow connections through older routers.

    The TCP/IP Options control panel lets you disable the Path MTU Discovery feature to support older network routers which don?t return the ?ICMP can't fragment? error. Disabling the feature provides the same behavior as MacTCP. (Note that disabling the feature may introduce a performance penalty in some network configurations.)

    WARNING: Misuse of the TCP/IP Options control panel may prevent Open Transport TCP/IP from operating properly.
     

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