CIDR Contains
Check if IP is in CIDR.
How to use CIDR Contains
CIDR Contains — Report whether an IP address is inside a CIDR prefix. Free to use in D2i DevTools — no account required.
Steps
- Fill in CIDR. This field is required.
- Fill in IP. This field is required.
- Click Run and copy the result under the form.
Frequently asked questions
What is CIDR Contains used for?
Use it to test allow lists, subnet questions, and routing examples.
How do I use the free online CIDR Contains tool?
Fill in CIDR. This field is required. Fill in IP. This field is required. Click Run and copy the result under the form.
What can I paste or upload into CIDR Contains?
Enter a CIDR such as 192.0.2.0/24 and an IP such as 192.0.2.15. Both must be the same family to match.
What output does CIDR Contains give me?
The word contained or not contained. An unparseable CIDR or IP returns an error instead.
Is CIDR Contains free, and is my input private?
Yes — Your input is processed in memory for this request only. It is not saved to disk or the database, and it is cleared after the tool finishes.
Does the network address itself count as contained?
Yes. The first and last addresses of the prefix are inside it, including a /32 that contains only that one address.
Inputs are processed in memory only and are not saved to disk or the database. Data exists only for the duration of your request.