Sort IP Addresses

Why a normal sort gets it wrong

A plain text sort compares character by character, so 10.0.0.10 lands before 10.0.0.2 and 100.1.1.1 before 20.1.1.1. This sort reads each number between the dots as a number.

Good for

• Blocklists and allowlists for .htaccess, nginx, firewalls and fail2ban
• IPs pulled from access logs. Use Count duplicates to see which addresses appear most often
• Inventory and DHCP reservation lists

Lines with extra text, like Deny from 10.0.0.2, sort correctly as long as they all start the same way. CIDR ranges like /24 sort with their base address. IPv6 addresses are sorted as text.

A blocklist

192.168.1.20
10.0.0.10
192.168.1.3
10.0.0.2
8.8.8.8
192.168.1.3
172.16.0.0/12

8.8.8.8
10.0.0.2
10.0.0.10
172.16.0.0/12
192.168.1.3
192.168.1.20

Try this example