---
name: "nfanon"
section: "1"
platform: "linux"
package: "nfdump"
version: "1.7.5-2+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nfanon"
---

# nfanon(1)

anonymize the IP addresses

## NAME

**nfanon** – anonymize the IP addresses

## SYNOPSIS

**nfanon** **-r** *path* \[**-w** *nffile*\] **-K** *key* \[**-q**\] \[**-h**\]

## DESCRIPTION

**nfanon** anonimizes all IP addresses ( src, dst, next hop, router IP etc. ) in the netflow  records using the CryptoPAn (Cryptography-based  Prefix-preserving Anonymization) module. The key -K is used to initialize the Rijndael cipher. The key is either  a 32 character string, or a 64 hex digit string starting with 0x. See  https://en.wikipedia.org/wiki/Crypto-PAn for more information on CryptoPAn.

The source specified by argument **-r** *path* may point to a single nfdump file or to a directory containing many nfdump files. All files in a directory are processed recursively.

If the output argument **-w** *nffile* is given, all anonimized records are written into that single file, even if the  source is a directory. If no argument **-w** is specified,  **nfanon** overwrites the original source file with the anonymized flow records. If the source is a directory, each flow file is anonymized respectively.

The options are as follows:

- **-r** *path*

  Path to read flow files to anonymize. Path may point to a single file or a directory containing many flow files.

- \[**-w** *nffile*\]

  File name to write anonymized flow records to. If this argument is missing, the source file name is taken, which means the original file is overwritten.

- **-k** *key*

  *key* is either a 32 character string, or a 64 char hex string starting with 0x. This key is used to initialize the anonymizer.

- **-q**

  **nfanon** prints the file name to be processed and an actifivy spinner. This option disables both.

- **-h**

  Print help text to stdout and exit.

## EXAMPLES

To create a random 64 character hex string you may use the following command:

```
% xxd -u -l 32 -p -c 64 /dev/urandom
```

Use the resulting output as key, prepended with 0x as -K argument.

## RETURN VALUES

**nfanon** returns 0 on success and 255 otherwise.

## SEE ALSO

[nfdump(1)](/nfdump/1.md)