ufwを有効にした後、sshからロックアウトされました

Question

UfwでSSHとHTTPの両方を有効にしました。 Ubuntu16.04でのLinodeVPSの使用。

Sudo ufw enableを実行した後、Webブラウザー経由でアクセスできる仮想コンソールを除いて、事実上ロックアウトされています。

これが私のリスニングデーモンです：

Sudo netstat -lvpnut

Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 4387/mysqld tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 4385/sshd tcp6 0 0 :::80 :::* LISTEN 11543/Apache2 tcp6 0 0 :::22 :::* LISTEN 4385/sshd

Ufwを無効にすると、sshで戻ることができます。

Ufwを有効にしたSudo ufw status verboseは次のとおりです。

Status: active Logging: on (low) Default: deny (incoming), allow (outgoing), disabled (routed) New profiles: skip To Action From -- ------ ---- 22 ALLOW IN Anywhere 80 ALLOW IN Anywhere 22 (v6) ALLOW IN Anywhere (v6) 80 (v6) ALLOW IN Anywhere (v6)

iptables -nvLの出力は次のとおりです。

Chain INPUT (policy DROP 1 packets, 60 bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy DROP 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain DOCKER (0 references) pkts bytes target prot opt in out source destination Chain DOCKER-ISOLATION (0 references) pkts bytes target prot opt in out source destination 2360 18M RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 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 0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:137 0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:138 0 0 ufw-skip-to-policy-input tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:139 0 0 ufw-skip-to-policy-input tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:445 0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:67 0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:68 0 0 ufw-skip-to-policy-input all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type BROADCAST Chain ufw-after-logging-forward (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix "[UFW BLOCK] " Chain ufw-after-logging-input (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix "[UFW BLOCK] " Chain ufw-after-logging-output (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix "[UFW ALLOW] " 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 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 3 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 4 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 11 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 12 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8 0 0 ufw-user-forward all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-before-input (0 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 0 0 ufw-logging-deny all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID 0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 3 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 4 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 11 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 12 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8 0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp spt:67 dpt:68 0 0 ufw-not-local all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT udp -- * * 0.0.0.0/0 224.0.0.251 udp dpt:5353 0 0 ACCEPT udp -- * * 0.0.0.0/0 239.255.255.250 udp dpt:1900 0 0 ufw-user-input all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-before-logging-forward (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW AUDIT] " Chain ufw-before-logging-input (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW AUDIT] " Chain ufw-before-logging-output (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW AUDIT] " Chain ufw-before-output (0 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * lo 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 0 0 ufw-user-output all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-logging-allow (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix "[UFW ALLOW] " Chain ufw-logging-deny (2 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID LOG flags 0 level 4 prefix "[UFW AUDIT INVALID] " 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix "[UFW BLOCK] " Chain ufw-not-local (1 references) pkts bytes target prot opt in out source destination 0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL 0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type MULTICAST 0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type BROADCAST 0 0 ufw-logging-deny all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 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-skip-to-policy-forward (0 references) pkts bytes target prot opt in out source destination 0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-skip-to-policy-input (7 references) pkts bytes target prot opt in out source destination 0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-skip-to-policy-output (0 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 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 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 ctstate NEW 0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 ctstate NEW Chain ufw-user-forward (1 references) pkts bytes target prot opt in out source destination Chain ufw-user-input (1 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22 0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:22 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:80 Chain ufw-user-limit (0 references) pkts bytes target prot opt in out source destination 0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 5 LOG flags 0 level 4 prefix "[UFW LIMIT BLOCK] " 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain ufw-user-limit-accept (0 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 Chain ufw-user-logging-forward (0 references) pkts bytes target prot opt in out source destination Chain ufw-user-logging-input (0 references) pkts bytes target prot opt in out source destination Chain ufw-user-logging-output (0 references) pkts bytes target prot opt in out source destination Chain ufw-user-output (1 references) pkts bytes target prot opt in out source destination

私は何が間違っているのですか？

ravishi · Answer

これは、ufwがNBD（Network Block Device）へのVPS接続をブロックしているため、サーバーがクラッシュするためと考えられます。VPSプロバイダーとしてscalewayを使用していますが、同じ問題が発生しました。これを防ぐには、 https://community.online.net/t/how-to-configures-iptables-with-input-rules-with-dynamic-nbd/303/22 を確認してください。