92 lines
3.9 KiB
Groff
92 lines
3.9 KiB
Groff
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.TH IFCHD 8 2011-07-12 Linux "Linux Administrator's Manual"
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.SH NAME
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ifchd \- interface change daemon
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.SH SYNOPSIS
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.B ifchd
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.RI [ OPTION ]...
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.SH DESCRIPTION
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The ifchd daemon changes network interface configuration information
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(such as the IP address, broadcast address, subnet, etc) as well as
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resolv.conf, the machine hostname, and other similar system configuration
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bits on the request of authorized clients such as ndhc instances.
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.SH OPTIONS
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.TP
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.BR \-d ,\ \-\-detach
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Immediately fork into the background. This is the default behavior.
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.TP
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.BR \-n ,\ \-\-nodetach
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Do not fork into the background. Useful for debugging or initial setup.
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.TP
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.BR \-q ,\ \-\-quiet
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Don't print to standard out, standard error, or syslog.
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.TP
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.BI \-c\ CHROOTDIR ,\ \-\-chroot= CHROOTDIR
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This option specifies the directory to which ifchd should confine itself via
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chroot() after startup. This directory should be shared with associated ndhc
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daemons, and should have access to dev/urandom and dev/null. For logging to
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work, a dev/log socket or device should also exist.
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.TP
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.BI \-r\ RESOLVCONF ,\ \-\-resolve= RESOLVCONF
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Specifies the path to the system resolv.conf. This file will typically be in
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/etc/resolv.conf. If this option is specified, ndhc will update the contents
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of this file to match the DNS servers specified by the remote DHCP server. If
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this option is not specified, ifchd will never change the system DNS resolution
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configuration.
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.TP
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.BR \-o ,\ \-\-hostname
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If specified, ifchd will update the system host name in response to any
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hostname option field provided by a remote DHCP server on the request of
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a ndhc client. If this option is not specified, ifchd will never change
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the system hostname.
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.TP
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.BI \-p\ PIDFILE ,\ \-\-pidfile= PIDFILE
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Write the process id number of the ifchd instance into the specified file name.
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The default is to not write the process id number into any file at all.
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.TP
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.BI \-u\ USER ,\ \-\-user= USER
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This option specifies the user name or user id that ifchd will change to after
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startup. This user should be unique to the ifchd daemon.
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.TP
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.BI \-g\ GROUP ,\ \-\-group= GROUP
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This option specifies the group name or group id that ifchd will change to
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after startup.
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.TP
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.BI \-U\ CLIENTUSER ,\ \-\-cuser= CLIENTUSER
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This option specifies the user name or user id that will be required of
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processes that wish to make interface change requests of ifchd. Any other
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users will be denied a connection to the ifchange socket.
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.TP
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.BI \-G\ CLIENTGROUP ,\ \-\-cgroup= CLIENTGROUP
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This option specifies the group name or group id that will be required of
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processes that wish to make interface change requests of ifchd. Any other
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groups will be denied a connection to the ifchange socket.
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.TP
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.BI \-P\ CLIENTPID ,\ \-\-cpid= CLIENTPID
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This option specifies the process id that will be required to make interface
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change requests of ifchd. Any process that has a process id that does not
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equal this value will be denied a connection to the ifchange socket.
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.TP
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.BI \-i\ INTERFACE ,\ \-\-interface= INTERFACE
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Specifies an interface by name (such as 'eth0') on which ifchd is allowed to
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make configuration changes (such as IP address, subnet mask, etc). Multiple
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interfaces may be whitelisted by using this switch multiple times.
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.TP
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.BR \-V ,\ \-\-verbose
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Print detailed messages. Useful for debugging or setup.
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.TP
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.BR \-h ,\ \-\-help
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Print basic help information and exit.
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.TP
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.BR \-v ,\ \-\-version
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Display the ifchd version number and copyright information.
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.SH SIGNALS
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It is not necessary to sleep between sending signals, as signals received are
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processed sequentially in the order they are received. ifchd does not
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perform any unusual behavior on receipt of signals.
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.SH NOTES
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ifchd is rather minimal and doesn't do exotic things like change NTP server
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configuration. This is intentional, since it needs to run as CAP_NET_ADMIN,
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which although far less powerful than root, still gives it a fair amount
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of privileged behavior.
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