il faut configurer un peu plus la règle

base/activation-manuelle/service-fail2ban.nix

@@ -42,11 +42,15 @@ mkIf cfg.fail2ban {
           action   = route[blocktype=blackhole]
           maxretry = 3
         '';
+        ssh-mail-whois = ''
+          filter   = sshd
+          maxretry = 3
+          action   = mail-whois[dest=${destemail}]
+        '';
       };
     };
   };
 
   # https://github.com/NixOS/nixpkgs/issues/8437
   services.fail2ban.jails.ssh-iptables = "enabled = true";
-  services.fail2ban.jails.mail-whois-lines = "enabled = true";
 }