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    SubjectRe: How to survive in a Micro$oft environment??
    On Sat, 26 Feb 2000, Theodore Y. Ts'o wrote:
    >Given my past experience with certain broken HP Printer drivers (for
    >Windows) that would SNMP sweep an entire class A network at high speed,
    >I'm less convinced that this kind of scanning is *ever* appropriate.

    Well, having worked for an ISP and currently working for Make Systems
    (we make network modeling software), there is a place for this, BUT IT
    I didn't run a specifically designed network discovery tool, then this
    should not happen. A fucking printer driver shouldn't even know what
    SNMP is.

    >Especially since given the use of CIDR, there's absolutely no guarantee
    >that a class C subnet is going to be local. More often than not, people
    >routinely get fractions of a class C these days, and the rest will go
    >out over a potentially slow link.

    And likewise, the DNS server the application is looking for may not be on
    the same network.

    >... Also, a company that has this kind of firewall is
    >also likely to have a DHCP or BOOT infrastructure, which is something
    >else that *really* should be tried first. In fact, the order that
    >should be used is probably:
    > * DHCP/BOOT
    > * IN-ADDR lookup of NS records
    > * DNS capetbombing of local subnet with ttl set to 1

    Didn't it already use DHCP to get an IP address? How many DHCP servers don't
    send back DNS server data as well? At any rate, people should stop trying
    to make their installers such smart-asses. Ask the damned operator before
    you "drop back and punt." Odds are, the person installing things knows the
    DNS server addresses. And if they don't, the installer can give them the
    _option_ of sending megabytes of junk to hundreds of machines in the off-
    chance they'll handle DNS for you.

    If you ever have to scan a range of addresses, it's probablly in your best
    interest to ask the monkey with the keyboard for some input/guidance.


    PS: I'm all to well aware of the ever dwindling average intellegence on linux
    users, but I still advocate asking a stupid user before doing something
    even stupider.

    PPS: Even windows will ask for DNS settings in the absence of DHCP. No DNS
    in the DHCP data == NO DNS unless you specify the settings.

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