55 lines
1.9 KiB
Plaintext
55 lines
1.9 KiB
Plaintext
ndhc client
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--------------------
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The ndhc client negotiates a lease with the DHCP server and notifies
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ifchd when a leases is obtained or lost.
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command line options
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-------------------
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The command line options for the ndhc client are:
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-c, --clientid=CLIENTID Client identifier
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-H, --hostname=HOSTNAME Client hostname
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-h, Alias for -H
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-f, --foreground Do not fork after getting lease
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-b, --background Fork to background if lease cannot be
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immediately negotiated.
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-i, --interface=INTERFACE Interface to use (default: eth0)
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-n, --now Exit with failure if lease cannot be
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immediately negotiated.
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-q, --quit Quit after obtaining lease
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-r, --request=IP IP address to request (default: none)
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-v, --version Display version
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If the requested IP address cannot be obtained, the client accepts the
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address that the server offers.
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note on ndhc's random seed
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---------------------------
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ndhc will seed its random number generator (used for generating xids)
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by reading /dev/urandom. If you have a lot of embedded systems on the same
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network, with no entropy, you can either seed /dev/urandom by a method of
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your own, or doing the following on startup:
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ifconfig eth0 > /dev/urandom
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in order to seed /dev/urandom with some data (mac address) unique to your
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system. If reading /dev/urandom fails, ndhc will fall back to its old
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behavior of seeding with time(0).
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signals accepted by ndhc
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-------------------------
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ndhc also responds to SIGUSR1 and SIGUSR2. SIGUSR1 will force a renew state,
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and SIGUSR2 will force a release of the current lease, and cause ndhc to
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go into an inactive state (until it is killed, or receives a SIGUSR1). You do
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not need to sleep between sending signals, as signals received are processed
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sequentially in the order they are received.
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