Sorry guys for a very simple question, but I couldn't find the correct way to replace the last octet (is this the correct word for it) with a "0".

So far I tried several things, after searching these forums, but or it replaces 1 number (not 1, 2 or 3 numbers after the last dot).

Here are 3 examples:

In all these cases the last (.1, .22 or .333) need to replaced with a 0. Reason for this is I want to put these annoying IP's who try to access SSH in a block list permantly.

So far all solutions I found don't give a correct result. Maybe someone has a working regex for Notepad++ to do this?

Thanks in advance.

  • I want to put these annoying IP's who try to access SSH in a block list permantly i think you make a mistake. Most part of Internet nodes have a mask which differs from /24. You may block excess addresses. Including addresses which may not be blocked - for example, public or commercial proxies, or eved datacenters which hosts such nodes.
    – Akina
    Dec 19 '19 at 17:10

It's much more efficient without capture groups:

  • Ctrl+H
  • Find what: \d+$
  • Replace with: 0
  • CHECK Wrap around
  • CHECK Regular expression
  • Replace all


\d+         # 1 or more digits
$           # end of line

Screen capture (before):

enter image description here

Screen capture (after):

enter image description here

  • 1
    Applicable if each line contais IP address only. But, given that this is a list of IP-addresses, it's a smart decision.
    – Akina
    Dec 19 '19 at 17:08
  • 1
    Nice clean and detailed solution. This solution is nicer imho therefor accepting this one as answer. TY!
    – Joanne
    Dec 20 '19 at 8:19
Find: ((\d{1,3}.){3})\d{1,3}
Replace: \10

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