When specifying an iprange in data collection -> discovery

192.168.4.0/24 is NOT equivalent to 192.168.4.0-255, but the difference is not documented or explained.

 

192.168.4.0/24 really means 192.168.4.1-254 (the network and broadcast addresses are excluded), but when specified as 192.168.4.0-255 they are then included.

The fix part: Furthermore, specifying this as an attempt to override does not work:

192.168.4.0/24,192.168.4.255

(I think the parser throws away the 192.168.4.255 as its (supposedly) already covered by the 192.168.4.0/24) (later code then checks if a range was specified by CIDR or not and excludes the network/broadcast accordingly).

This (ignoring the "overlapping" IP) should be corrected, or at least also documented.

 

In our case, the range we had issues with represented a bunch of /32 loopback addresses so there was no network or broadcast and we used the /cidr as a convenience (we use the entire /cidr as loopbacks and the zabbix documentation does not mention anything about the ends being excluded). When our device on .255 failed to get discovered I added the explicit IP, but it still failed to get discovered. replacing both with the 0-255 version then worked.

 

The documentation also shows ranges that exclude the network but include the broadcast (assuming the range represents a /24, implied by the other examples), which may be confusing in the context of the surrounding examples.