|RDNSSD(8)||System Manager's Manual||RDNSSD(8)|
rdnssd parses RDNSS options and keeps track of resolvers to write nameservers entries to a resolv.conf(5) configuration file. By default, it writes its own separate file, and may call an external hook to merge it with the main /etc/resolv.conf. This is aimed at easing coexistence with concurrent daemons, especially IPv4 ones, updating /etc/resolv.conf too.
On Linux, since version 2.6.24, rdnssd takes advantage of a new netlink interface, forwarding RDNSS options validated by the kernel to userland. Otherwise, it merely listens to all ICMPv6 traffic through a raw socket.
- -f or --foreground
- Do not detach from the console. Run the program in the foreground.
- -H merge-hook or --merge-hook merge-hook
- Execute this hook whenever resolv.conf is updated. If this option is not specified, then no hook will be called.
- -h or --help
- Display some help and exit.
- -p pidfile or --pidfile pidfile
- Override the location of the pidfile.
- -r resolv-file or --resolv-file resolv-file
- Set the path to the generated resolv.conf file.
- -u username or --user username
- Override the user that the program will run as. By default, it runs as nobody.
- -V or --version
- Display program version and license and exit.
- A basic merge hook shipped with rdnssd, to be called with the -H option.
- The default resolv.conf(5) file that rdnssd writes its configuration to.
- The process-id file.
When rdnssd uses a raw socket instead of the netlink kernel interface, it does not validate received Neighbor Discovery traffic in any way. For example, it will always consider Router Advertisement packets, whereas it should not if the host is configured as a router. When the netlink interface is used, such validation is done by the kernel.