Re: [9fans] telnet vs. godaddy whois - Plan9

This is a discussion on Re: [9fans] telnet vs. godaddy whois - Plan9 ; > rfc 742 p. 42 says > > [...] If the the user signals a push function then the > data must be sent even if it is a small segment. > > by "illegal" i mean goes contrary to ...

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Thread: Re: [9fans] telnet vs. godaddy whois

  1. Re: [9fans] telnet vs. godaddy whois

    > rfc 742 p. 42 says
    >
    > [...] If the the user signals a push function then the
    > data must be sent even if it is a small segment.
    >
    > by "illegal" i mean goes contrary to an rfc "must." perhaps
    > i'm missing something.


    i don't see how what was sent is contrary to that requirement.

    >sensible as setting PSH on a pure ACK.


    i don't understand this reference to a `pure' ACK. it's an ACK! in TCP/IP every
    packet after SYN must have an ACK (or that really is -- explicitly -- illegal).
    the ACK and PSH have nothing to do with each other.
    in fact, the receiver isn't handling the PSH oddly because it's associated
    with an ACK, but because it misinterpreted the standard, or the standard isn't clear.



  2. Re: [9fans] telnet vs. godaddy whois

    >> rfc 742 p. 42 says
    >>
    >> [...] If the the user signals a push function then the
    >> data must be sent even if it is a small segment.
    >>
    >> by "illegal" i mean goes contrary to an rfc "must." perhaps
    >> i'm missing something.

    >
    > i don't see how what was sent is contrary to that requirement.
    >
    >>sensible as setting PSH on a pure ACK.

    >
    > i don't understand this reference to a `pure' ACK. it's an ACK! in TCP/IP every
    > packet after SYN must have an ACK (or that really is -- explicitly -- illegal).
    > the ACK and PSH have nothing to do with each other.
    > in fact, the receiver isn't handling the PSH oddly because it's associated
    > with an ACK, but because it misinterpreted the standard, or the standard isn't clear.


    By pure I assume he meant an ACK with no data, which is what I
    also meant by "plain ACK". But I agree with Charles here. After
    going back over the related sections of the RFC I don't see how
    this behavior violates anything in the standard. It's just not
    very common, and obviously not interpreted very well by this
    particular endpoint. Has anybody ever experienced this problem
    before with any of there P9 systems? I haven't.



  3. Re: [9fans] telnet vs. godaddy whois

    > Has anybody ever experienced this problem
    > before with any of there P9 systems? I haven't.


    not this particular problem, but years ago i had problems with plan 9 or perhaps it was inferno
    (originally) not implementing the window test correctly
    (leading to a RST storm with an incorrect AIX implementation),
    and difficulty talking to implementations that completely screwed up the handling of the wrap-around
    sequence number space, leading to needless disconnects depending on initial sequence number.
    one was a tcp/ip implementation that's still popular in the embedded space.



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