デフォルトでは、Container-Optimized OS のホスト ファイアウォールを使用すると SSH サービスのみを介した発信接続と受信接続が許可されます。Container-Optimized OS を実行している VM インスタンスで sudo iptables -L を実行することで、正確なホスト ファイアウォール構成を確認できます。
[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["わかりにくい","hardToUnderstand","thumb-down"],["情報またはサンプルコードが不正確","incorrectInformationOrSampleCode","thumb-down"],["必要な情報 / サンプルがない","missingTheInformationSamplesINeed","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-09-04 UTC。"],[[["\u003cp\u003eBy default, Container-Optimized OS allows outgoing connections and only accepts incoming connections via SSH, as seen with the \u003ccode\u003esudo iptables -L\u003c/code\u003e command, but this might vary with other Google Cloud products.\u003c/p\u003e\n"],["\u003cp\u003eUsing Docker's \u003ccode\u003e-p\u003c/code\u003e option automatically configures the host firewall for network accessibility when deploying a container on Container-Optimized OS without \u003ccode\u003e--net=host\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor IPv6 accessibility, the host firewall must be manually configured using \u003ccode\u003eip6tables\u003c/code\u003e commands because Docker does not automatically configure the IPv6 rules.\u003c/p\u003e\n"],["\u003cp\u003eWhen deploying a container on Container-Optimized OS with Docker's \u003ccode\u003e--net=host\u003c/code\u003e option, you must manually configure the host firewall with \u003ccode\u003eiptables\u003c/code\u003e commands.\u003c/p\u003e\n"],["\u003cp\u003eTo ensure persistent host firewall configurations across reboots when using \u003ccode\u003eiptables\u003c/code\u003e commands, utilize \u003ccode\u003ecloud-init\u003c/code\u003e to set up the firewall rules, such as allowing incoming TCP connections on port 80.\u003c/p\u003e\n"]]],[],null,["# Configuring the host firewall\n\nBy default, the Container-Optimized OS host firewall allows outgoing\nconnections and accepts incoming connections only through the SSH service. You\ncan see the exact host firewall configuration by running `sudo iptables -L` on a\nVM instance running Container-Optimized OS.\n| **Warning:** The default firewall configuration might be different if you are using Container-Optimized OS through another Google Cloud product like [Containers on Compute Engine](/compute/docs/containers/deploying-containers) or Google Kubernetes Engine. Refer to the product specific documentation for more details.\n\nKeep in mind that the host firewall is different from Virtual Private Cloud firewall\nrules, which must also be configured for your applications to work correctly.\nSee the [Firewall Rules Overview](/vpc/docs/firewalls) to learn more about\nVirtual Private Cloud firewall rules.\n\nRunning containers in Docker's default network namespace\n--------------------------------------------------------\n\nIf you are deploying a container on Container-Optimized OS that must be\naccessible over the network and you are not using Docker's `--net=host` option,\nrun your container with Docker's `-p` option. With this option, Docker will\nautomatically configure the host firewall to expose your application on the\nnetwork. See the\n[Docker run reference](https://docs.docker.com/engine/reference/run/) to learn\nmore about Docker run options.\n\nIn the following example, the `nginx` container will be accessible on the\nnetwork on port 80: \n\n docker run --rm -d -p 80:80 --name=nginx nginx\n\n| **Note:** If IPv6 address is used for accessing the deployed container over the network, you must explicitly configure the host firewall using `ip6tables` commands like `\"ip6tables -A INPUT -p tcp --dport 80 -j ACCEPT\"`.This is because Docker does not automatically configure the IPv6 rules for host firewall to expose your application on the network due to [known limitation](https://github.com/moby/moby/issues/21951).\n\nRunning containers in the host's network namespace\n--------------------------------------------------\n\nIf you are deploying a container on Container-Optimized OS that must be\naccessible over the network and you are using Docker's `--net=host` option, you\nmust explicitly configure the host firewall yourself.\n\nYou can configure the host firewall with standard `iptables` commands. As with\nmost GNU/Linux distributions, firewall rules configured with `iptables` commands\nwill not persist across reboots. To ensure that the host firewall is correctly\nconfigured on every boot, configure the host firewall in your `cloud-init`\nconfiguration. Consider the following `cloud-init` example: \n\n #cloud-config\n\n write_files:\n - path: /etc/systemd/system/config-firewall.service\n permissions: 0644\n owner: root\n content: |\n [Unit]\n Description=Configures the host firewall\n\n [Service]\n Type=oneshot\n RemainAfterExit=true\n ExecStart=/sbin/iptables -A INPUT -p tcp --dport 80 -j ACCEPT\n - path: /etc/systemd/system/myhttp.service\n permissions: 0644\n owner: root\n content: |\n [Unit]\n Description=My HTTP service\n After=docker.service config-firewall.service\n Wants=docker.service config-firewall.service\n\n [Service]\n Restart=always\n ExecStart=/usr/bin/docker run --rm --name=%n --net=host nginx\n ExecStop=-/usr/bin/docker exec %n -s quit\n\n runcmd:\n - systemctl daemon-reload\n - systemctl start myhttp.service\n\nUsing this `cloud-init` configuration with a VM running\nContainer-Optimized OS will result in the following behaviors on every\nboot:\n\n- The host firewall will be configured to allow incoming TCP connections on port 80.\n- An `nginx` container will listen on port 80 and respond to incoming HTTP requests.\n\nRefer to\n[Creating and configuring instances](/container-optimized-os/docs/how-to/create-configure-instance)\nto learn more about using `cloud-init` on Container-Optimized OS."]]
