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IPTABES 和 Docker - 为什么我无法连接到容器化的 PostgreSQL 服务？

tag-icon • tag-icon iptables docker postgresql
IPTABES 和 Docker - 为什么我无法连接到容器化的 PostgreSQL 服务？

我正在学习如何实现 iptables 规则。我目前有以下规则：

#!/bin/sh

iptables -F

iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

iptables -A INPUT -i eth0 -p tcp -m multiport --dports 22,80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp -m multiport --sports 22,80,443 -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A OUTPUT -o eth0 -p tcp -m multiport --dports 80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m multiport --sports 80,443 -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A OUTPUT -o eth0 -p udp -m multiport --dports 53 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p udp -m multiport --sports 53 -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A INPUT -j REJECT
iptables -A OUTPUT -j REJECT
iptables -A FORWARD -j REJECT

这些规则应该很容易遵循：

- Start from scratch
- Allow local traffic
- Allow incoming ssh, www traffic
- Allow outgoing www traffic
- Allow outgoing dns traffic
- Disallow all other traffic

现在我生成一个 PostgreSQL 服务器，如下所示：

docker run -p 5432:5432 postgres

我现在想要在主机中连接到该 PostgreSQL 容器：

psql -U postgres -h localhost

我正进入（状态：

psql: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.

当我没有按照上面所述执行 iptables 规则时，我不会收到此错误。

我原本期望 Docker 在启动/删除容器时动态添加/删除规则，以允许访问开放端口。

iptables -S：启动后的规则

-P INPUT DROP
-P FORWARD DROP
-P OUTPUT DROP
-N DOCKER
-N DOCKER-ISOLATION
-N DOCKER-USER
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -p tcp -m multiport --dports 22,80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A INPUT -i eth0 -p tcp -m multiport --sports 80,443 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i eth0 -p udp -m multiport --sports 53 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-port-unreachable
-A FORWARD -j DOCKER-USER
-A FORWARD -j DOCKER-ISOLATION
-A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -o docker0 -j DOCKER
-A FORWARD -i docker0 ! -o docker0 -j ACCEPT
-A FORWARD -i docker0 -o docker0 -j ACCEPT
-A FORWARD -j REJECT --reject-with icmp-port-unreachable
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -o eth0 -p tcp -m multiport --sports 22,80,443 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p tcp -m multiport --dports 80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p udp -m multiport --dports 53 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -j REJECT --reject-with icmp-port-unreachable
-A DOCKER-ISOLATION -j RETURN
-A DOCKER-USER -j RETURN

iptables -S：docker run postgres 后的规则

-P INPUT DROP
-P FORWARD DROP
-P OUTPUT DROP
-N DOCKER
-N DOCKER-ISOLATION
-N DOCKER-USER
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -p tcp -m multiport --dports 22,80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A INPUT -i eth0 -p tcp -m multiport --sports 80,443 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i eth0 -p udp -m multiport --sports 53 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-port-unreachable
-A FORWARD -j DOCKER-USER
-A FORWARD -j DOCKER-ISOLATION
-A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -o docker0 -j DOCKER
-A FORWARD -i docker0 ! -o docker0 -j ACCEPT
-A FORWARD -i docker0 -o docker0 -j ACCEPT
-A FORWARD -j REJECT --reject-with icmp-port-unreachable
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -o eth0 -p tcp -m multiport --sports 22,80,443 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p tcp -m multiport --dports 80,443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p udp -m multiport --dports 53 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -j REJECT --reject-with icmp-port-unreachable
-A DOCKER -d 172.17.0.2/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 5432 -j ACCEPT
-A DOCKER-ISOLATION -j RETURN
-A DOCKER-USER -j RETURN

正如您在倒数第三行看到的，已添加一条规则以允许传入 5432。

答案1

-i lo意味着回送仅接口。虽然 Docker 容器是“本地的”，但它们不要使用环回接口——它们使用虚拟以太网接口连接到主机。

由于您没有允许传出或传入 PostgreSQL 流量的规则，因此它会被阻止。

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