> ## Documentation Index
> Fetch the complete documentation index at: https://e2b.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Why does iptables fail with 'xt_owner module missing' in a sandbox?

The `xt_owner` kernel module is not currently available in E2B's sandbox kernel. As a result, iptables rules that depend on it (most commonly `NAT REDIRECT` with `--uid-owner` or `--gid-owner`, used in transparent proxy setups) will fail with:

```
Warning: Extension owner revision 0 not supported, missing kernel module?
```

The command exits with code 4, which aborts any script running under `set -e`.

## Workaround: use nftables

[nftables](https://wiki.nftables.org/wiki-nftables/index.php/Main_Page) is the modern replacement for iptables and does not depend on the `xt_owner` module for owner-based matching. If you're setting up a transparent proxy or any rule that matches on user/group ownership, use nftables instead.