Re: nftables: drop ssh brute force with ip block

["Irwin L." <biatche@gmail.com>]

On 2016-06-23 18:48, Pablo Neira Ayuso wrote:
> On Thu, Jun 23, 2016 at 06:39:46PM +0800, Irwin L. wrote:
>> I currently use:
>> tcp dport {22222,40022,42222} ct state new counter flow table bruteforce {
>> ip saddr limit rate 3/minute } counter accept comment "limit bruteforce"
>>
>> Is this ok?
> Looks good to me. I would probably check for ct state new in first
> place, given that this only matches the first packet a new TCP
> connections. It will save you the tcp dport set lookup.
>
> Note that you can even limit this per port, ie.
>
>          ct state new tcp dport {22222,40022,42222} counter \
>                  flow table bruteforce { ip saddr . tcp dport limit rate 3/minute } \
>                          counter accept comment "limit bruteforce"
>
> using the 'ip saddr . tcp dport' concatenation. But I guess you want
> globally ban anyone spamming you to those ports anyway.
>
>> I wanted to ban spamming ips altogether, but I've since learned that this is
>> the job of 'fail2ban'
> fail2ban is nice to have to simplify this administrative hassle, but I
> think it is still using iptables (it's been a while a I didn't look at
> that code), we can do much better now with nft to resolve this problem.

By that do you mean "counter ct state new" instead of "counter flow table" ?

Thing is with this method, it only limits, I wonder if nft can blacklist 
the ip for 1 day or even 1 week with the option of manually removing 
blacklisted ips manually.