Hello,

i have found the IP range 120.76.0.0 - 120.79.255.255 that i want to ban in iptables the way i write x.x.x.x/xx format. Please how to know what that x.x.x.x/xx should be? I have found some online tool where i enter the range and it return it, but unable, these tools like https://www.calculator.net/ip-subnet-calculator.html only have field for single IP and subnet mask.

If you do not know what a CIDR is or how to calculate one I seriously question whether you are ready to or should be dealing directly with iptables. Although it is not that difficult it is far too easy to cause serious problems for yourself. I would advise learning more about the basics of iptables (or nftables) and having some understanding and facility with binary before attempting. However, to your question. The CIDR you are looking for is 120.76.0.0/14. A look at the iptables-extensions man page would also show you you really don't need the CIDR. Using the iprange match --src-range will also work.

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See also:

https://community.spiceworks.com/net...-a-subnet-mask

https://www.cidr.eu/en/ipv4

That is for IPv4. IPv6 is quite different, on many levels.


Then for NFTables, try starting here:

https://wiki.nftables.org/wiki-nftab..._in_10_minutes

https://www.linuxsecrets.com/archlin.../Nftables.html

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Agree with agillator, but again question why someone with more than SIX YEARS experience using iptables needs to ask such questions:
https://www.linuxquestions.org/quest...st-4175678169/
https://www.linuxquestions.org/quest...ps-4175614728/

...among many others that are iptables related. And you asked a similar question THREE YEARS ago, and one before that dealing with subnets and iptables; why can you not apply anything you've been told or learned???
https://www.linuxquestions.org/quest...ed-4175610321/
https://www.linuxquestions.org/quest...em-4175572252/

:-)
1) go to https://community.spiceworks.com/tools/subnet-calc/ and set Number of subnets 1
2) if one's range is the range of some provider that should be banned, then the provider's range (subnet/CIDR format) may be found like this: go to Linux terminal and do command "whois x.x.x.x|grep route" where x.x.x.x is some IP within the rage. It should show CIDR format with /subnetmask.

Right; that's what you were told in agillators first reply, and were even handed a link to the subnet calculator from Turbocapitalist.

And again: you asked about this SEVEN YEARS AGO, and were handed the commands, because you (apparently) can't put any effort into learning for yourself, or applying what you're told. Is there some point that you're going to be able to do things on your own?

Ish...ARIN and RIPE usually publish the CIDR of the containing range. Other registries are less consistent.
I downloaded two perl scripts — I don’t recall from where — cidr.pl and cidr_range.pl that will convert ranges to cidr notation and vice versa.
DDG is your friend. Try searching for either script name. Let us know if you can’t find them.

I wish you luck; check the OP's posting history.