Nsupdate change serial

There may be several keys that permit one to update a DNS. Note that it is important that the "key" file and "private" file have the same stem path since one cannot be used without the other. Unconditionally deleting a DNS record eg. If your key was authorised to make the request, the DNS will update its database, update its journal files, increment the serial number of the SOA record, and send a change notification to any slave DNSes. There are a couple of points to keep in mind.

All updates in one "send" batch must be for the same zone. For example, one cannot mix changes for example. In addition, there seems to be an undocumented limit in nsupdate of how many updates can be in one batch, probably due to a fixed input buffer. I have found that requests at a time sometimes do not pass. If this sounds obvious, it's not.

You may send nsupdate requests as frequently as your cronjob says to lookup only nameservers. With the right nameserver listed first in the supersede statement, you hitthe right machine first. This means that the dhcp info does not stomp on resolv. I also configure an internal alias on my nic, so I don't need two nics. This does not work with samba for some reason; it just doesn't. The shell script above needs to be called by dhclient whenever it runs and also in a cron job.

Make sure the script contains absolute paths good habit to everything. I have several domains doing simultaneous updates. To make any changes to zones to which you are allowing nsupdate you will need to comment out the "allow-update" lines in named. Key based updating prevents any manual updates from registering with named. The -v option makes nsupdate use a TCP connection. This may be preferable when a batch of update requests is made. The -t option sets the maximum time an update request can take before it is aborted.

The default is seconds. Zero can be used to disable the timeout. The -u option sets the UDP retry interval. The default is 3 seconds. If zero, the interval will be computed from the timeout interval and number of UDP retries.

The -r option sets the number of UDP retries. The default is 3. If zero, only one update request will be made. Each command is supplied on exactly one line of input. Some commands are for administrative purposes. The others are either update instructions or prerequisite checks on the contents of the zone. These checks set conditions that some name or set of resource records RRset either exists or is absent from the zone.

These conditions must be met if the entire update request is to succeed. Updates will be rejected if the tests for the prerequisite conditions fail.