[ntp:questions] Is there something with greater detail on "interface" besides the manpage?

Rick Jones rick.jones2 at hp.com
Mon Nov 18 23:17:14 UTC 2013

Is there a resource out there with a description of the "interface"
configuration file command, beside the text in the ntp.conf manpage?
I started at ntp.org, followed a command index link that took me to
http://www.eecis.udel.edu/~mills/ntp/html/miscopt.html#interface but
all that says is:

interface [listen | ignore | drop] [all | ipv4 | ipv6 | wildcard | name | address[/prefixlen]]

    This command controls which network addresses ntpd opens, and
    whether input is dropped without processing. The first parameter
    determines the action for addresses which match the second
    parameter. That parameter specifies a class of addresses, or a
    specific interface name, or an address. In the address case,
    prefixlen determines how many bits must match for this rule to
    apply. ignore prevents opening matching addresses, drop causes
    ntpd to open the address and drop all received packets without
    examination. Multiple interface commands can be used. The last
    rule which matches a particular address determines the action for
    it. interface commands are disabled if any -I, --interface, -L, or
    --novirtualips command-line options are used. If none of those
    options are used and no interface actions are specified in the
    configuration file, all available network addresses are
    opened. The nic command is an alias for interface.

Which is nice for as far as it goes but I'm sufficiently clueless that
I need something which goes farther.

In particular, I have a situation with a system with a Very Large (tm)
and dynamic number of interfaces, which I think is causing the ntpd to
become Quite Unhappy (tm) (perhaps running out of filedescriptors -
1024 being the current ulimit but that is just a guess).  It simply
goes "poof" without anything particularly descriptive in syslog.

Anyway, I really don't need/want it trying to listen on > 99% of them,
but I also have multiple systems whereon the name(s) of the interfaces
I do want ntpd to listen on may not be the same and a Strong Desire
(tm) to have the same config file everywhere.  They do though share a
common prefix and I was wondering if something like "interface listen
foo*" could be used.  Or, for that matter "interface ignore bar*"


rick jones
Don't anthropomorphize computers.  They hate that.  - Anonymous
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

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