You may want to block the login or phone registration by IP address in 3CX if you are sure your business will be totally local.

Download the database file

We will use the database file (CSV) from https://db-ip.com/db/download/ip-to-country-lite

(And a copy of the version May 2020 can be downloaded here)

Open it with Excel, and format as table, then you can filter by the country code, copy the part you want to block, which will looks like below:

User a formula =[@A1]&”-“&[@A2] in D1, apply to all the D column, then D column will looks like: 2.16.103.0-2.16.103.255, select all D column, copy. Select E column, right click, choose selective paste, then choose value.

Convert to CIDR format

The 3CX only accept the CIDR format, so we need to convert the data first.

Doing this manually can be daunting , luckily, we can use an online tool to convert them :

Then copy E column, open https://www.ipconvertertools.com/iprange2cidr#, choose multiple IP ranges,  paste your data in the text area. click Calculate.

After a few seconds, it will show the:

Click the Export to CSV, choose Comma separated, Download the CSV file, open with Excel, delete every column except the first one, rename the title to IP, add another two column: expirationDate, and description. The correspond value will be date value : 2119-10-08T14:53:00+00:00 , and a description “Russia”, because I copied the IP addresses for Russia.

Modified into:

Save this as a CSV file, which will be converted into JSON by another online tool.

Convert to the JSON format

https://www.convertcsv.com/csv-to-json.htm

Under Step 1: Select your input, click Choose file and select the CSV file.

Under Step 2: Choose input options (optional), tick 

[
{
"IP": "2.16.103.0/25",
"expirationDate": "2119-10-08T14:53:00+00:00",
"description": "Russia"
},
{
"IP": "2.16.103.128/26",
"expirationDate": "2119-10-08T14:53:00+00:00",
"description": "Russia"
},
...

]

Import into 3CX