IP spreadsheet checker
Check an IP allocation sheet before it causes an outage. Upload an Excel or CSV file, or paste a list, and see every invalid entry, duplicate block, overlap and block that doesn't start on its boundary, with the row it is on.
Runs in your browser. Nothing you enter or upload is sent to us.
How to use it
Three steps
- Add your sheet. Choose an .xlsx or .csv file, or paste the column of addresses. The first sheet in an Excel file is read.
- Pick the column. The checker finds the column that looks most like addresses. Choose another column, or every column, if you need to.
- Fix what it finds. Each finding shows the row and what is wrong. Download the report as CSV to share it or work through it.
Questions
Good to know
Is my file uploaded anywhere?
No. The file is read by your own browser, on your computer. Nothing is sent to Helpnyx or anyone else.
What does it check?
That every entry is a valid IPv4 or IPv6 address or block; that no block is listed twice; that no block overlaps or sits inside another; and that each block starts on its boundary (10.0.0.5/24 should be written 10.0.0.0/24). It can also note private and reserved ranges.
Why is a block inside another block a problem?
If 203.0.113.16/28 is given to one customer and 203.0.113.20/30 to another, the same addresses belong to both. That is how duplicate-IP outages start.
What about ranges like 192.0.2.10 - 192.0.2.20?
Ranges are reported as not valid blocks. Use the CIDR and range converter to turn them into blocks first.
How do I stop this happening again?
IPAM Enterprise checks every new assignment for overlaps before it is saved, and its Excel import shows conflicts before anything is written.
More free tools
Other tools you may need
/24 planner
Split a /24 into customer, link and LAN blocks on a map.
Open the toolAddress in subnet check
Find which of your blocks holds each address.
Open the toolIPv4 subnet calculator
Network, broadcast, usable range and masks for any block.
Open the toolIPv6 subnet calculator
First and last address, size, /64 count and reverse zone.
Open the toolSubnet mask cheat sheet
Every prefix from /8 to /32 with masks and host counts.
Open the toolCIDR and range converter
Turn first-to-last ranges into CIDR blocks, and back.
Open the tool
Still tracking IPs in a spreadsheet?
IPAM Enterprise keeps every /24, block, customer and circuit in one portal, and checks each assignment for overlaps before it is saved.