Sorry, it looks not very consistent to allow save the discovery rule with an empty important field.
You could create discovery rule with Disabled status and with some dummy IP range. Later, before using this discovery rule, you can update it to required IP range and enable it.
I agree that it with be very inefficient. I guess the real feature I'm requesting is the ability to disable and remove hosts that have already been added to zabbix but are no longer online – ones which were added passively using an auto-registration rule. There are discovery rules for this, but they must have some sort of inherency passed down to them from a separate discovery check that uses IP ranges.
With AWS we're unable to scan IP ranges as its not practical. We have all of our hosts being added passively via an auto-registration rule. We just need a way to efficiently clear them out (remove them from groups, unlink them from templates, etc) when they go offline in the cloud.
We're doing this via a periphery script and the zabbix API, but simply allow us to define a rule that will disable/remove a host based on a set of parameters would be most useful.
Thanks for creating such a great product. I really like the changes in 2.0.
> With AWS we're unable to scan IP ranges as its not practical.
Could you please share experience why it is not practical ?
> We just need a way to efficiently clear them out (remove them from groups, unlink them from templates, etc) when they go offline in the cloud.
Your request about the empty IP range value will not work anyhow.
How zabbix server can execute a discovery action when it cannot scan a network because the discovery rule doesn't have the IP range ?
I think another ZBXNEXT should be created 
All vanilla ec2 machines from Amazon's cloud have an unpredictable backlan address somewhere in the range of 10.0.0.0/8 ... that's just too many IPs to scan
For this reason we use auto-registration with active agents. The machines come online and phone home to the Zabbix server. This works perfectly for our needs. I'm very happy with auto-registration in 2.0.
However, Discovery in this context is being used to disable and remove old hosts that no longer exist anywhere but in Zabbix. They are gone forever, but poor Zabbix wants to check on them every once in awhile. I'm using the Zabbix API to manually remove them at the moment.
Since we have a record of all hosts, why can't we say something as simple as "check known hosts" instead of an IP range for discovery? Or even just allow a certain trigger to disable hosts, remove it from groups, etc.. In fact, giving triggers the power to manipulate hosts in this fashion would be very useful indeed!
Thanks for getting back to me. If that request makes sense I can form it into a new ZBXNEXT I'm sure other people using ec2 instances or the cloud would appreciate this feature as well!
See continuation on ZBXNEXT-1387
I believe this can be closed as we have already ZBXNEXT-1387
Feel free to reopen if do not agree.
reopen to manage labels
closed again
Stephen, please consider upvoting https://support.zabbix.com/browse/ZBXNEXT-1347 as I think it will (partly) implement what you are looking for.