Linux Netfilter discussions
 help / color / mirror / Atom feed
From: Randy Bush <randy@psg.com>
To: "Kerin Millar" <kfm@plushkava.net>
Cc: netfilter@vger.kernel.org
Subject: Re: prefix len confusion
Date: Wed, 10 Jun 2026 09:33:05 -0700	[thread overview]
Message-ID: <m2o6hi1hku.wl-randy@psg.com> (raw)
In-Reply-To: <6fcf67b9-4fee-4b1c-85f1-597afff788ba@app.fastmail.com>

> table ip raw {
>     chain PREROUTING {
>         type filter hook prerouting priority raw;
>         ip daddr 42.642.11.82 tcp dport 22 meta nftrace set 1
>     }
> }
> 
> 
> Next, run "nft monitor trace".

thanks a million.  this showed pretty conclusively that the
`/etc/nftables.conf` was indeed correct and filtering as one
would hope/expect.  and i learned a new hack!

so we are now looking for more subtle attack surface, e.g. loose
source routing, bouncing off a legitimately open service on the
same LAN, etc.

we also see this (distributed source) attack on proxmox clusters' web
interfaces

    2026-06-07T02:01:39.274405+00:00 pv0 pvedaemon[2276]: authentication failure; rhost=::ffff:85.11.167.7 user=root@pam msg=Authentication failure
    2026-06-07T02:01:42.970943+00:00 pv0 pvedaemon[2277]: authentication failure; rhost=::ffff:85.11.167.7 user=root@pam msg=Authentication failure

can we safely just add ffff::0 to the v6 bogon list?

randy

  parent reply	other threads:[~2026-06-10 16:33 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-10  0:10 prefix len confusion Randy Bush
2026-06-10  0:51 ` Kerin Millar
2026-06-10  1:01   ` Randy Bush
2026-06-10  1:26     ` Kerin Millar
2026-06-10  1:32       ` Randy Bush
2026-06-10  1:38         ` Kerin Millar
2026-06-10 16:33       ` Randy Bush [this message]
2026-06-10 16:53         ` Kerin Millar
2026-06-10 17:19           ` Randy Bush
2026-06-10 18:02             ` Kerin Millar
2026-06-10 23:51               ` Sunny73Cr
2026-06-10 23:57                 ` Randy Bush
2026-06-11  0:06                   ` Sunny73Cr
2026-06-11  0:25                     ` Randy Bush
2026-06-11  1:05                 ` Kerin Millar
2026-06-11  1:12                   ` Randy Bush
2026-06-10  6:20     ` Reindl Harald
2026-06-10 10:09       ` Kerin Millar
2026-06-10 16:01       ` Randy Bush

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=m2o6hi1hku.wl-randy@psg.com \
    --to=randy@psg.com \
    --cc=kfm@plushkava.net \
    --cc=netfilter@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox