Ubuntu 20.04、fail2ban は IP を禁止して iptables に格納しますが、禁止された IP は引き続き接続でき、fail2ban ログには IP がすでに禁止されていると表示されます。

Ubuntu 20.04、fail2ban は IP を禁止して iptables に格納しますが、禁止された IP は引き続き接続でき、fail2ban ログには IP がすでに禁止されていると表示されます。

Ubuntu 20.04。/var/log/nginx/access.log に次のような大量のレコードがあります。

85.249.25.218 - - [15/Dec/2020:08:12:15 +0300] "POST /api/v1/device/analytics HTTP/1.1" 404 162 "-" "okhttp/4.8.1"

fail2ban をインストールしました。/etc/fail2ban/jail.local の内容は次のとおりです。

[sshd]
enabled   = true
maxretry  = 3
findtime  = 1w
bantime   = 4w
protocol  = all
port      = all
banaction = iptables-allports

[nginx-botsearch]
enabled   = true
maxretry  = 3
findtime  = 1w
bantime   = 4w
protocol  = all
port      = all
logpath   = %(nginx_error_log)s
banaction = iptables-allports

[nginx-custom2]
enabled   = true
maxretry  = 3
findtime  = 1w
bantime   = 4w
protocol  = all
port      = all
logpath   = %(nginx_access_log)s
banaction = iptables-allports

/etc/fail2ban/filter.d/nginx-custom2.conf をフィルターします:

[Definition]
failregex = ^<HOST>.*GET \/api\/v1\/device\/.*
            ^<HOST>.*POST \/api\/v1\/device\/.*
            ^<HOST>.*PUT \/api\/v1\/device\/.*
ignoreregex =

Fail2ban は私が関心のある IP を禁止し、それらを iptables に格納します。fail2ban-client -v status nginx-custom2 の出力は次のようになります。

Status for the jail: nginx-custom2
|- Filter
|  |- Currently failed: 11
|  |- Total failed: 2962
|  `- File list:    /var/log/nginx/access.log
`- Actions
   |- Currently banned: 88
   |- Total banned: 88
   `- Banned IP list:   176.59.129.174 176.59.129.44 176.59.130.124 176.59.132.106 176.59.133.195 176.59.134.14 176.59.142.78 176.59.146.203 176.59.151.46 176.59.193.194 176.59.194.205 176.59.200.101 176.59.200.92 176.59.201.16 176.59.201.174 176.59.32.58 176.59.32.99 176.59.33.4 176.59.33.43 176.59.33.86 176.59.34.97 176.59.38.189 176.59.39.47 176.59.43.227 176.59.46.102 176.59.46.210 176.59.49.240 176.59.52.215 176.59.68.151 176.99.82.18 178.176.48.132 178.67.194.209 178.67.196.94 188.113.141.148 213.234.251.192 213.27.48.88 213.87.250.113 217.118.64.2 217.118.93.139 31.13.144.102 31.173.241.11 31.173.80.23 37.29.40.213 37.29.41.108 37.29.41.208 46.187.12.73 46.45.200.129 62.133.162.154 80.83.237.30 80.83.237.34 83.149.21.218 83.234.120.247 85.115.243.47 85.115.248.16 85.115.248.250 85.140.0.111 85.140.0.159 85.140.0.9 85.140.1.20 85.140.1.225 85.140.12.183 85.140.19.132 85.140.2.127 85.140.4.36 85.140.4.92 85.174.194.255 85.174.198.90 85.249.163.166 85.249.25.218 85.26.164.108 85.26.164.151 85.26.165.234 85.26.165.238 85.26.232.91 85.26.233.73 85.26.235.207 89.113.138.149 89.113.138.255 89.113.139.227 89.113.140.202 89.178.132.99 93.88.25.3 95.153.129.19 95.153.129.237 109.197.205.118 85.115.248.36 176.59.140.152 176.59.68.199

iptables -L -n -v の出力は次のようになります。

Chain INPUT (policy ACCEPT 419 packets, 175K bytes)
 pkts bytes target     prot opt in     out     source               destination         
23438 6327K f2b-nginx-custom2  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
22460 6268K f2b-nginx-botsearch  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
22460 6268K f2b-sshd   all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 412 packets, 60919 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain f2b-nginx-botsearch (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 REJECT     all  --  *      *       87.26.121.231        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       8.129.209.71         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       47.98.190.243        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       171.244.49.242       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       157.131.240.194      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       149.129.137.131      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       128.106.166.8        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       103.76.228.45        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       103.44.245.166       0.0.0.0/0            reject-with icmp-port-unreachable
22460 6268K RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain f2b-nginx-custom2 (1 references)
 pkts bytes target     prot opt in     out     source               destination         
  117  7020 REJECT     all  --  *      *       176.59.68.199        0.0.0.0/0            reject-with icmp-port-unreachable
   58  3480 REJECT     all  --  *      *       176.59.140.152       0.0.0.0/0            reject-with icmp-port-unreachable
   72  4320 REJECT     all  --  *      *       85.115.248.36        0.0.0.0/0            reject-with icmp-port-unreachable
    7   420 REJECT     all  --  *      *       109.197.205.118      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       95.153.129.237       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       95.153.129.19        0.0.0.0/0            reject-with icmp-port-unreachable
   23  1380 REJECT     all  --  *      *       93.88.25.3           0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       89.178.132.99        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       89.113.140.202       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       89.113.139.227       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       89.113.138.255       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       89.113.138.149       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.235.207        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.233.73         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.232.91         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.165.238        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.165.234        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.26.164.151        0.0.0.0/0            reject-with icmp-port-unreachable
   17  1020 REJECT     all  --  *      *       85.26.164.108        0.0.0.0/0            reject-with icmp-port-unreachable
   32  1920 REJECT     all  --  *      *       85.249.25.218        0.0.0.0/0            reject-with icmp-port-unreachable
  189 11340 REJECT     all  --  *      *       85.249.163.166       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.174.198.90        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.174.194.255       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.4.92          0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.4.36          0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.2.127         0.0.0.0/0            reject-with icmp-port-unreachable
   15   900 REJECT     all  --  *      *       85.140.19.132        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.12.183        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.1.225         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.1.20          0.0.0.0/0            reject-with icmp-port-unreachable
   40  2400 REJECT     all  --  *      *       85.140.0.9           0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.0.159         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.140.0.111         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.115.248.250       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.115.248.16        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       85.115.243.47        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       83.234.120.247       0.0.0.0/0            reject-with icmp-port-unreachable
   66  3960 REJECT     all  --  *      *       83.149.21.218        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       80.83.237.34         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       80.83.237.30         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       62.133.162.154       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       46.45.200.129        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       46.187.12.73         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       37.29.41.208         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       37.29.41.108         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       37.29.40.213         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       31.173.80.23         0.0.0.0/0            reject-with icmp-port-unreachable
   12   720 REJECT     all  --  *      *       31.173.241.11        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       31.13.144.102        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       217.118.93.139       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       217.118.64.2         0.0.0.0/0            reject-with icmp-port-unreachable
    7   420 REJECT     all  --  *      *       213.87.250.113       0.0.0.0/0            reject-with icmp-port-unreachable
    4   240 REJECT     all  --  *      *       213.27.48.88         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       213.234.251.192      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       188.113.141.148      0.0.0.0/0            reject-with icmp-port-unreachable
  210 12600 REJECT     all  --  *      *       178.67.196.94        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       178.67.194.209       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       178.176.48.132       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.99.82.18         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.68.151        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.52.215        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.49.240        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.46.210        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.46.102        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.43.227        0.0.0.0/0            reject-with icmp-port-unreachable
    7   420 REJECT     all  --  *      *       176.59.39.47         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.38.189        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.34.97         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.33.86         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.33.43         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.33.4          0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.32.99         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.32.58         0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.201.174       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.201.16        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.200.92        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.200.101       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.194.205       0.0.0.0/0            reject-with icmp-port-unreachable
  102  6120 REJECT     all  --  *      *       176.59.193.194       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.151.46        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.146.203       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.142.78        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.134.14        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.133.195       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.132.106       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.130.124       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.129.44        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       176.59.129.174       0.0.0.0/0            reject-with icmp-port-unreachable
22460 6268K RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain f2b-sshd (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    9   724 REJECT     all  --  *      *       110.16.95.6          0.0.0.0/0            reject-with icmp-port-unreachable
   18  1384 REJECT     all  --  *      *       113.190.235.28       0.0.0.0/0            reject-with icmp-port-unreachable
   45  3192 REJECT     all  --  *      *       94.191.38.203        0.0.0.0/0            reject-with icmp-port-unreachable
   20  1556 REJECT     all  --  *      *       14.232.214.138       0.0.0.0/0            reject-with icmp-port-unreachable
   18  1424 REJECT     all  --  *      *       222.252.30.29        0.0.0.0/0            reject-with icmp-port-unreachable
   31  2268 REJECT     all  --  *      *       146.59.157.181       0.0.0.0/0            reject-with icmp-port-unreachable
   11   660 REJECT     all  --  *      *       110.35.79.23         0.0.0.0/0            reject-with icmp-port-unreachable
   20  1512 REJECT     all  --  *      *       190.202.32.2         0.0.0.0/0            reject-with icmp-port-unreachable
   23  1732 REJECT     all  --  *      *       190.79.227.81        0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       103.127.108.96       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       103.123.246.130      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       101.36.110.215       0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       101.109.245.158      0.0.0.0/0            reject-with icmp-port-unreachable
    0     0 REJECT     all  --  *      *       1.245.61.144         0.0.0.0/0            reject-with icmp-port-unreachable
21387 6197K RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0           

Chain ispmgr_allow_ip (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ispmgr_allow_sub (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ispmgr_deny_ip (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ispmgr_deny_sub (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-logging-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-logging-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-logging-output (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-after-output (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-logging-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-logging-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-logging-output (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-before-output (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-reject-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-reject-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-reject-output (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-track-forward (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-track-input (0 references)
 pkts bytes target     prot opt in     out     source               destination         

Chain ufw-track-output (0 references)
 pkts bytes target     prot opt in     out     source               destination 

しかし、/var/log/nginx/access.log に、すでに禁止されている IP からのレコードがまだ表示されます。また、/var/log/fail2ban.log には、次のようなレコードが多数表示されます。

2020-12-15 08:23:38,156 fail2ban.actions [2803]: WARNING [nginx-custom2] 83.149.21.218 already banned

ここからどこへ行けばよいのか教えてください。

答え1

ufw出力にチェーンが表示されています。を使用しているiptablesネット フィルター バックエンドは でしょうか? 私の記憶が正しければ、バックエンド スイッチは 20.10 までに Ubuntu で予定されていますが、おそらく自分で変更したか、何らかのサービスがインストールされたのでしょう (この場合は、nftables 禁止アクションに切り替えたほうがよいでしょう)。ufwnftables

低レベルのネットフィルターを使用する場合は間違いではありませんが、ufw を使用する場合、fail2ban で ufw 禁止アクションを使用することに反対する理由は何でしょうか?

そして、ispmanager はまだあるようです...

とにかく、iptables にすべてのチェーン (ispmgr_*およびufw-*) が表示されていますが、それらへの参照はありません。したがって、設定がおかしいか、このシステムのファイアウォール サブシステムに問題があるかのどちらかです。

それは VM ですか? (もしそうなら、どれですか?)...
システムで iptables カーネル モジュールが使用 (許可) されていますか?
また、ufw バックエンドは正確には何ですか?

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