Re: Debian 12 - IPv4 blocked without fail2ban & co

[Max Nikulin <manikulin@gmail.com>]

On 08/09/2023 04:39, Romain wrote:
> I can confirm that when this happens, it's the OVH server that fails to 
> send the response to my network.
>
> 35 9.862648672 MY_PUBLIC_IP_AT_HOME → 54.38.38.159 ICMP 78 Echo (ping) 
> request  id=0x4b30, seq=33150/32385, ttl=1
> 36 9.862704895 54.38.38.159 → MY_PUBLIC_IP_AT_HOME  ICMP 106 Destination 
> unreachable (Port unreachable)

Some intermediate firewall may have specific rules for ICMP.

It is better to try tcpdump (its capture file may be later loaded to 
wireshark) for HTTP and SSH packets at 54.38.38.159 and 192.168.0.2 
rpi4.home, or if your router allows it, even better at 192.168.0.1 
livebox.home.