e-mail attachments

Discussion in 'Asus' started by KenTak, Jun 27, 2003.

  1. KenTak

    KenTak Guest

    I am not able to send attachments by e-mail; I can receive them.
    I have P4PE with XP Pro installed; firewall disabled.
    I've tried Netscape 7.02, Mozilla 1.3, and Outlook 98;
    none have been able to send attachments.
    I've tried small and large files.

    Thanks for any help
    KenTak, Jun 27, 2003
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  2. Maybe there is a problem with your mail server, and not your computer?
    So you are using a pop server to send email?

    Fawad Chughtai, Jun 27, 2003
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  3. KenTak

    KenTak Guest

    I have checked with my ISP (Earthlink), and he finds no problems with that
    particular server.
    I use a pop server for incoming and smtp for outgoing.
    KenTak, Jun 28, 2003
  4. KenTak

    Paul Guest

    My ISP made a change to our mail server, where ICMP was disabled (so
    for example you cannot ping the server) and the MTU was changed to a
    value which happened to be 10 or 20 bytes less than the MTU of my
    router. This places the mail server in what I think is termed a
    "black hole". What happens is, when you send a large email, the
    email program sends full sized packets. Normally, TCP/IP would
    "discover" the MTU of the destination, using a function supported
    by ICMP. Something to do with whether to fragment the packet or
    not. Unfortunately, the protocol is such, that a server operating
    in a black hole, returns nothing to the sender, and the protocol
    freezes, because there is no retry by your computer. When I phoned
    tech support at my ISP, they were all sweet and innocent, explaining
    it was my fault that my MTU was too big, and would I reduce it.
    They didn't explain the change they made, which is normally
    implemented as some kind of protection against security or denial
    of service attacks on the mail server.

    Now that I've reduced my MTU, everything is back to normal. I
    hope tech support at Earthlink are more honest about what they
    have done with their server. It is quite possible the lowest
    tier individuals who answer the phone, know nothing of the details.

    Paul, Jun 28, 2003
  5. KenTak

    KenTak Guest

    Thanks for your reply.
    What is the MTU and how do I change it?
    KenTak, Jun 28, 2003
  6. KenTak

    Paul Guest

    You might also try and go to www.dslreports.com

    They have some "tools" to help you check/adjust the MTU as well as RWIN (early
    versions of Windoze set the latter to ~8192 and thus would limit throughput on
    broadband to around 700kbps instead of ~1500kbps---when considering average
    network latency).

    Paul, Jun 29, 2003
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