Re: prefix len confusion
Randy Bush <[email protected]> Tue, 09 Jun 2026 18:32:36 -0700
| Newsgroups | gmane.comp.security.firewalls.netfilter.general |
|---|---|
| Message-ID | <[email protected]> |
>> sorry for being insufficiently explicit
>>
>> the ssh attacker is getting through to 42.642.11.82, which is a piece of
>> hardware, not a vm. it is the ssh port of a hardware switch whose
>> security profile i prefer not to expose to attackers.
>>
>> define VULN4 = {
>> 42.642.11.34/31,
>> 42.642.11.36/31,
>> 42.642.11.40/29,
>> 42.642.11.48/29,
>> 42.642.11.80/30 # <<<====
>> }
>>
>> ip daddr $VULN4 drop
>
> In that case, the question becomes one of whether your nftables host
> is responsible for forwarding packets to "42.642.11.82" (as you put
> it) at all. And, just as importantly, from which source address.
the nftables is on the border router. and traceroute showed the path
in.
the sources of the attacks are a ddos, /82 logs the ssh attack as from a
jillion source addresses.
> Try incorporating the following table into your existing ruleset.
>
> 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".
sure, if only because i will learn a new hack :)
> If you do see output, study it, for it will conclusively show how the
> packets traverse your ruleset and why they are being accepted.
that would be lovely!!
thank you. will report back.
randy