CIDR - block everything

[expat1001]

Excuse me if this has been posted - I cannot find out how to to it including Google searches. I want to change phone authentication to whitelist, and block everything else. What CIDR notation should I use for the blacklist?

Thank you.

 

[NickD_3CX]

Hi there!

I'd suggest you check out a Training Module we have on security:
https://www.3cx.com/3cxacademy/videos/advanced/security-with-3cx-phone-system/

Generally though, when it comes to whitelisting specific IPs then blocking everything else, you would want to do that on your firewall, not 3CX.

 

[expat1001]

Thanks but is there a problem blocking everything on 3CX? I'd prefer that for organizational reasons. The info on that page is out of date. it does not use CIDR to set the IP range. I still don't know how to block everything that way.

 

[NickD_3CX]

The place where you add IPs to the Blacklist/whitelist is located in the Dashboard --> IP Blacklist.
The interface should be pretty self-explanatory, it even calculates the IP ranges for you:


If you don't fully understand this, it may be a good idea to ask a 3CX Partner for help.

Now whether or not you can block everything in 3CX except the IPs you want, theoretically you can, but you need to remember one thing:

• 3CX is a PBX, not a Firewall

What I mean with this is, you could, but don't, do it on your Firewall.

 

[expat1001]

Thanks but the only thing I am asking is the IP range and / mask to block everything.