Ubuntu
埠無法在 Ubuntu 16.04 上打開
我在 Hetzner 的 VPS 上安裝了 Ubuntu 16。我想打開我之前在其他 VPS 上做過幾次的埠 11121。
我試過ufw & iptables但是當我檢查時，我看到埠仍然關閉！
提示：這個 VPS 發生的唯一一件事是在 Hetzner 管理面板上勾選 RDNS，然後我在文本框中輸入了反向的公共 IP 並保存。但我不確定這一點，我再次刪除了它。我猜唯一的事情是這個動作及其對 NAT 配置的影響。
即使我通過 iptables 輸入了允許命令，但之後它返回以下狀態：
#iptables -L -nv Chain INPUT (policy ACCEPT 10248 packets, 4165K bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 10260 packets, 4288K bytes) pkts bytes target prot opt in out source destination然後我安裝了UFW，我嘗試手動打開一些埠，然後啟用UFW，下面是狀態：
# ufw status Status: active To Action From -- ------ ---- 11121 ALLOW Anywhere 22 ALLOW Anywhere 80 ALLOW Anywhere 443 ALLOW Anywhere 11121 (v6) ALLOW Anywhere (v6) 22 (v6) ALLOW Anywhere (v6) 80 (v6) ALLOW Anywhere (v6) 443 (v6) ALLOW Anywhere (v6)iptables 的狀態現在顯示如下：
# iptables -S -P INPUT DROP -P FORWARD DROP -P OUTPUT ACCEPT -N ufw-after-forward -N ufw-after-input -N ufw-after-logging-forward -N ufw-after-logging-input -N ufw-after-logging-output -N ufw-after-output -N ufw-before-forward -N ufw-before-input -N ufw-before-logging-forward -N ufw-before-logging-input -N ufw-before-logging-output -N ufw-before-output -N ufw-logging-allow -N ufw-logging-deny -N ufw-not-local -N ufw-reject-forward -N ufw-reject-input -N ufw-reject-output -N ufw-skip-to-policy-forward -N ufw-skip-to-policy-input -N ufw-skip-to-policy-output -N ufw-track-forward -N ufw-track-input -N ufw-track-output -N ufw-user-forward -N ufw-user-input -N ufw-user-limit -N ufw-user-limit-accept -N ufw-user-logging-forward -N ufw-user-logging-input -N ufw-user-logging-output -N ufw-user-output -A INPUT -j ufw-before-logging-input -A INPUT -j ufw-before-input -A INPUT -j ufw-after-input -A INPUT -j ufw-after-logging-input -A INPUT -j ufw-reject-input -A INPUT -j ufw-track-input -A FORWARD -j ufw-before-logging-forward -A FORWARD -j ufw-before-forward -A FORWARD -j ufw-after-forward -A FORWARD -j ufw-after-logging-forward -A FORWARD -j ufw-reject-forward -A FORWARD -j ufw-track-forward -A OUTPUT -j ufw-before-logging-output -A OUTPUT -j ufw-before-output -A OUTPUT -j ufw-after-output -A OUTPUT -j ufw-after-logging-output -A OUTPUT -j ufw-reject-output -A OUTPUT -j ufw-track-output -A ufw-after-input -p udp -m udp --dport 137 -j ufw-skip-to-policy-input -A ufw-after-input -p udp -m udp --dport 138 -j ufw-skip-to-policy-input -A ufw-after-input -p tcp -m tcp --dport 139 -j ufw-skip-to-policy-input -A ufw-after-input -p tcp -m tcp --dport 445 -j ufw-skip-to-policy-input -A ufw-after-input -p udp -m udp --dport 67 -j ufw-skip-to-policy-input -A ufw-after-input -p udp -m udp --dport 68 -j ufw-skip-to-policy-input -A ufw-after-input -m addrtype --dst-type BROADCAST -j ufw-skip-to-policy-input -A ufw-after-logging-forward -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] " -A ufw-after-logging-input -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] " -A ufw-before-forward -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A ufw-before-forward -p icmp -m icmp --icmp-type 3 -j ACCEPT -A ufw-before-forward -p icmp -m icmp --icmp-type 4 -j ACCEPT -A ufw-before-forward -p icmp -m icmp --icmp-type 11 -j ACCEPT -A ufw-before-forward -p icmp -m icmp --icmp-type 12 -j ACCEPT -A ufw-before-forward -p icmp -m icmp --icmp-type 8 -j ACCEPT -A ufw-before-forward -j ufw-user-forward -A ufw-before-input -i lo -j ACCEPT -A ufw-before-input -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A ufw-before-input -m conntrack --ctstate INVALID -j ufw-logging-deny -A ufw-before-input -m conntrack --ctstate INVALID -j DROP -A ufw-before-input -p icmp -m icmp --icmp-type 3 -j ACCEPT -A ufw-before-input -p icmp -m icmp --icmp-type 4 -j ACCEPT -A ufw-before-input -p icmp -m icmp --icmp-type 11 -j ACCEPT -A ufw-before-input -p icmp -m icmp --icmp-type 12 -j ACCEPT -A ufw-before-input -p icmp -m icmp --icmp-type 8 -j ACCEPT -A ufw-before-input -p udp -m udp --sport 67 --dport 68 -j ACCEPT -A ufw-before-input -j ufw-not-local -A ufw-before-input -d 224.0.0.251/32 -p udp -m udp --dport 5353 -j ACCEPT -A ufw-before-input -d 239.255.255.250/32 -p udp -m udp --dport 1900 -j ACCEPT -A ufw-before-input -j ufw-user-input -A ufw-before-output -o lo -j ACCEPT -A ufw-before-output -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A ufw-before-output -j ufw-user-output -A ufw-logging-allow -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW ALLOW] " -A ufw-logging-deny -m conntrack --ctstate INVALID -m limit --limit 3/min --limit-burst 10 -j RETURN -A ufw-logging-deny -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] " -A ufw-not-local -m addrtype --dst-type LOCAL -j RETURN -A ufw-not-local -m addrtype --dst-type MULTICAST -j RETURN -A ufw-not-local -m addrtype --dst-type BROADCAST -j RETURN -A ufw-not-local -m limit --limit 3/min --limit-burst 10 -j ufw-logging-deny -A ufw-not-local -j DROP -A ufw-skip-to-policy-forward -j DROP -A ufw-skip-to-policy-input -j DROP -A ufw-skip-to-policy-output -j ACCEPT -A ufw-track-output -p tcp -m conntrack --ctstate NEW -j ACCEPT -A ufw-track-output -p udp -m conntrack --ctstate NEW -j ACCEPT -A ufw-user-input -p tcp -m tcp --dport 11121 -j ACCEPT -A ufw-user-input -p udp -m udp --dport 11121 -j ACCEPT -A ufw-user-input -p tcp -m tcp --dport 22 -j ACCEPT -A ufw-user-input -p udp -m udp --dport 22 -j ACCEPT -A ufw-user-input -p tcp -m tcp --dport 80 -j ACCEPT -A ufw-user-input -p udp -m udp --dport 80 -j ACCEPT -A ufw-user-input -p tcp -m tcp --dport 443 -j ACCEPT -A ufw-user-input -p udp -m udp --dport 443 -j ACCEPT -A ufw-user-limit -m limit --limit 3/min -j LOG --log-prefix "[UFW LIMIT BLOCK] " -A ufw-user-limit -j REJECT --reject-with icmp-port-unreachable -A ufw-user-limit-accept -j ACCEPT編輯：
# netstat -tanp Active Internet connections (servers and established) 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 1121/mysqld tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 1127/redis-server 1 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1096/sshd tcp 0 332 172.31.1.100:22 5.116.231.153:28282 ESTABLISHED 7506/0 tcp6 0 0 :::443 :::* LISTEN 1158/apache2 tcp6 0 0 :::80 :::* LISTEN 1158/apache2 tcp6 0 0 :::22 :::* LISTEN 1096/sshd tcp6 0 0 172.31.1.100:80 155.94.88.138:54138 TIME_WAIT -
就我而言，問題不是在埠上執行服務。 實際上，該埠沒有監聽任何應用程序或服務。
正如您在netstat -tanp的以下輸出中看到的那樣，監聽時沒有埠：
# netstat -tanp Active Internet connections (servers and established) 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 1121/mysqld tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 1127/redis-server 1 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1096/sshd tcp 0 332 172.31.1.100:22 5.116.231.153:28282 ESTABLISHED 7506/0 tcp6 0 0 :::443 :::* LISTEN 1158/apache2 tcp6 0 0 :::80 :::* LISTEN 1158/apache2 tcp6 0 0 :::22 :::* LISTEN 1096/sshd tcp6 0 0 172.31.1.100:80 155.94.88.138:54138 TIME_WAIT -我沒有考慮這個事實，因為我相信服務像往常一樣執行並且我沒有錯誤！
特別感謝Michael Hampton和Nasir Riley在問題下的有益評論。