Docker Use Host Postfix

When working with multi-host, there is a need to use higher-level Docker orchestration tools to ease management of networking between a cluster of machines. To offer an alternative, or if you use a file for aws authentication, you could use docker volumes to mount these. The former approach seems better to me, but I'd like to be able to have dnsmasq also listen on the docker IP (172. MUP creates three docker containers for running the meteor app, nginx reverse proxy and mongo. docker run --rm --name postfix -p 1587:587 boky/postfix. Should I install and configure Postfix from inside the docker container? docker postfix. Step 1: Installing Apache2 and PHP7. Step 5: Add Hosts for Kubernetes cluster. Disadvantage The volume on the host is created automatically by Docker, and can be difficult to locate and use. Running Docker Toolbox and Docker for Mac on the same host You can run both Docker Toolbox and Docker for Mac on the same system, but not at the same time. This document describes 5 easy steps to setup your Postfix email server as smart host to relay on DNS Exit mail relay server for all email sendings. docker run –d –name –h –p: –isolation=hyperv All processes are listed in the hosts taskmanager with a job Task Id, which is unique for a container. To start using Docker that runs on a remote host: Go to Tools & Settings > Docker (under Server Management). My plan is to mount /var/log/mysql/ folder to local machine. In this case, it is assumed that postfix is not accessible to the outside world via SMTP. In Docker Tip #35 I wrote about connecting to your Docker host from inside of a container but a lot of things have changed since then. defaultRegistry), the shell to use when attaching to a Docker container (docker. --net=host: by default Docker will place a container into its own network stack. See this blog post for information about how to use iptables-persistent with the DOCKER-USER chain. PowerShell for Docker uses the Docker REST API to connect to Docker Engine. 1) so I can point docker hosts at that. exe and type in the following instructions:. Access your Secure Docker Registry. 99/mo! Host multiple sites affordably using Docker, Nginx…and SSD Nodes! Our Intel and SSD-backed servers and Tier-1 network connections give you the performance you need, for less. Just make sure to run newaliases each time you save the file. 117:80:80 larsks/simpleweb With this command, Docker will set up the standard network model: It will create a veth interface pair. Now, in your docker container, an entry in the /etc/hosts file will appear as follows: 172. The free "Community Edition" (CE) version of Docker for Windows is the preferred Docker solution for your Windows development host. Networked service-to-service communication use the CONTAINER_PORT. The Docker daemon is what actually executes commands sent to the Docker Client — like building, running, and distributing your containers. At each step, we'll cover instructions specific to the following operating systems:. Connect to Any Docker Registry Docker Cloud allows you to connect to any registry that supports the Docker Registry API. Developers/operators can easily move to Podman, do all the fun tasks that they are familiar with from using Docker, and do much more. Enter your Cloud Server host name or a fully-qualified domain name. For example, docker network create -o "com. This week we host the team behind Flow, the awesome project management suite for teams, that uses Buddy to deploy and monitor their marketing site. Researchers have found what they are calling the first crpytojacking worm to spread to and from compromised containers in the Docker Engine. Only use docker-latest if you want to try it out as a standalone service, because it is not compatible with other container tools available with Atomic Host and RHEL Server, unless docker and docker-latest are the same version. 03+ you can use the host. We create a container using docker run. I resorted to Vagrant. After getting the mail system running and able to send mail from the host, I tried to configure it in WordPress. Now, to work with docker you will need to install docker-engine in your host. Google Cloud Platform Community tutorials submitted from the community do not represent official Google Cloud Platform product documentation. Optionally, the container can be committed, so that (for example) manual QA could be performed by the container being imported into a local docker provider, and run from there. And then, if you got them right, it will just seem to have ignored you and unchecked the share, without telling you that anything went wrong. This step-by-step guide will help you successfully launch a Linux virtual machine on Amazon EC2 within our AWS Free Tier. Docker Networking with Multiple Hosts. In my use case I had to configure it with HTTP, because we didn’t have the certificate nor the knowledge on how to obtain it. The attackers use the exposed APIs to execute commands on the Docker hosts which allow them to manage containers (start, stop, or kill), as well as create new ones by deploying a images from a. com relay_user_1:password_1 @domain2. If not, use docker start to start it. If the container is not crucial at this moment (for example, it is performing some batch work), we can free it to allow other programs to run faster. Docker is preferred by many system admins and developers to maximize their creativity in an App production environment. /logs:/var/log/mysql ) from docker-compose then logs files are showing on container. Using a GO template we filtered the output of docker inspect command to fetch IP address only. docker) submitted 8 months ago by p_r_m_n_ Does anybody know the best way to add custom host specific environment variables to a container with docker swarm. In this post, I’m going to show you how to use macvlan interfaces with Docker for networking. Mail Transfer Agent. Use the port you exposed in the docker run command. yaml file, you won't see any CSS or JS files being served. If you're managing more than one server and can manage your Office365 domain please see my updated post Better Use of Office 365 as a Smart Host with Postfix. If you are using docker machine, run the script shipped with the product that sets up the environment. Docker Machine is a tool that makes it easy to provision and manage multiple Docker hosts remotely from your personal computer. yml may be updated when Ubersmith is upgraded. Even in the absence of docker-machine one can still create a remotely accessible Docker Host on a Windows Server 2016 VM. Now install docker using the apt command below. Please stick. Let’s take a look at the iptables rule set and see what it has… No rule to allow http. One way is to force the container to use the same network as the host by using the parameter --network host:. py code is localhost and I use docker-compose. It knows how to recognize many common configuration errors and gives a grade. You don't use dedicated IP addresses. Often the host machine will have an IP 172. 8) My host /etc/resolv. First make sure that nc command is available within your docker container by installation of nectcat package. Using SMTP on Azure. The best way to configure a Docker Container is using environment variables, Gunicorn does not natively support this. If you haven't read this blog post, then please do so before continuing here. Update April 2019: The DNS name is now called host. This is the start of a Docker container that will forward mail using postfix. Avoiding conflicts between the container and the Docker host Postfix instances Public DNS records. In this tutorial, we will use Postfix as our MTA. For example, Linux containers cannot run directly on Windows Docker hosts. Docker creates three networks automatically on install: bridge, none, and host. The same way you would have configured when not using Gmail as reply in postfix. The longer the server has been running for, the better the advice mysqltuner can provide. Content in the 'HowTos' hierarchy is written because its author believes it to work (one assumes) and to provide value as a reference. Using Docker as a Jenkins Cloud Provider. yml file that runs the application services and the Eventuate Local. Yet another enthusiast blog! Docker for your users - Introducing user namespace 2015 #postfix #spam #sysadmin Force a remote host to reboot via VNC. Run Angular in a Docker Container using Multi-Stage builds. addr" privnet. Suppose you have a web application that links against a database and this postfix container. To start off this series we will use the sameersbn/bind docker image to setup a DNS server in production and host only environments. DOCKER_HOST Daemon socket to connect to. $ docker run -it --rm --link=postfix alpine sh $ telnet postfix 25 HELO foo. Because you can access GPUs while using a Docker container, it's also a great way to link Tensorflow or any dependencies your machine learning code has so anyone can use your work. postfix running within the container, with port 25 reachable specifically on 192. I want to use the postfix which is installed on the host. Think of the Qualys SSL server tester as an analogy: it is a great tool to quickly check a webserver to see use of SSL has been properly configured, and identify opportunities for improving the configuration to provide stronger encryption. Enter your Cloud Server host name or a fully-qualified domain name. Docker images for Kibana are available from the Elastic Docker registry. However, I was unable to connect to the host machine from the container on the Docker host IP address. Setup Postfix with a remote SMTP relay host. Exposing Postfix to the docker network, that is, Postfix must be configured to bind to localhost as well as the docker network. This tutorial will guide you through running multiple websites on a Google Compute Engine instance using Docker. 04 LTS systems. The container has received the IP 172. Oct 29, 2017 · # Use syslog-ng to get Postfix logs (rsyslog uses upstart which does not seem # to run within Docker). My e-mail ID is brain, and I have my account on howstuffworks. Flexibility to support microservices and traditional app workloads. The whole the process will be automated using a Dockerfile. To provide an example of how you might move to containerized development, I built a simple todo API using. This document describes 5 easy steps to setup your Postfix email server as smarthost to relay through DNS Exit mail relay server for all email sending. Sign up run postfix with smtp authentication (sasldb) in a docker container. Use a FQDN (host. Suppose you want to expose the container's port 8080 (standard http port) on the host's port 80 (assuming that port is not in use). It can be difficult, however, to refer to the same volume over time when it is an anonymous volumes. Popular orchestration tools today include Docker Swarm, Kubernetes, and Apache Mesos. Later if you wish to re-configure a particular parameter, you can either run the command or. sudo systemctl stop postfix sudo apt remove postfix && apt purge postfix 2. 2 Japanese: Ansible Tower Quick インストールガイド v3. Can anyone help to solve the problem? Really appreciated the help. I'd appreciate any critique of what I could do better. Researchers have found what they are calling the first crpytojacking worm to spread to and from compromised containers in the Docker Engine. Docker - Images - In Docker, everything is based on Images. Collecting Docker infrastructure logs describes how to collect Docker logs (both host logs and container stdout) using syslog-ng running in a container and reading the hosts journal. Managing Remote Services. Using the site configs below will forward ACME requests to mailcow and let it handle certificates itself. These containers are unique because they bring together all the dependencies of an application into a single package and deploy it. Start your docker container, using the -p option to bind exposed ports to an ip address and port on the host: # docker run -d --name web -p 10. This has very serious security implications - namely, code inside the container can now run as root on your Docker host. We will then use it to serve a simple web page from our home directory - all without the need to install a web server on our host. Using the host timezone in a docker container I was recently asked if there was a docker option available to set the timezone in a container. Since Docker containers share the host computer's operating system, if you want to run or test the same application on different operating systems, you will need to use virtual machines instead of Docker. What is Docker? Docker is a technology where you make an image of your application along with the environment setup. We will then fix some of the issues that it warns us about. I wanted to run an application that is linux base that I can successfully run in windows docker (linux container) but without access to the gpu but still using tensorflow. However, Docker does not take the. A new Vagrant-file will be used to explain the Docker host VM. It was really easy for DNS or Web Server. Docker is an open-source project that allows you to use predefined images to run applications in independent “containers” that are run within a single Linux instance. In this tutorial we are going to learn how to set up an Email server using Postfix, Dovecot and Squirrelmail on CentOS 7. I am assuming here that you already have pulled a Docker image for use. This week we host the team behind Flow, the awesome project management suite for teams, that uses Buddy to deploy and monitor their marketing site. When GitLab Runner is started as a system service (e. /logs:/var/log/mysql ) from docker-compose then logs files are showing on container. Check your configuration ¶. docker run --rm --name postfix -p 1587:587 boky/postfix. Each web container is linked to a mail container with Postfix configured with AWS SES. The CentOS Project is a community-driven free software effort focused on delivering a robust open source ecosystem around a Linux platform. Get a Docker container IP address from host using container ID. 04 and explore the basic Docker Compose concepts and commands. 06/26/2019; 6 minutes to read; In this article. 04 and explore the basic Docker concepts and commands. With this delivery method, smtp configuration is specified using async_smtp_settings keyword instead of smtp_settings keyword:. Gunicorn supports a configuration file that can contain Python code, we will use this feature to be able to pass environment variables to configure it. For more information on LE architecture, see the Little endian and Linux on IBM Power Systems website. In this article, we will use Docker Compose to create a MongoDB server and then another container that is used exclusively as a MongoDB client. docker-mailserver alternatives and similar software solutions Based on the "Complete solutions" category. Catchpoint unveils Network Insights, an out-of-the-box network visibility solution. The Docker tasks you used in the build pipeline when you created the build artifacts push the Docker image back into your Azure Container Registry. So, although both macvlan network called `macvlan` on both hosts, the docker engine on host-A has no idea what is the IP of `dog-db` on host-B. How to Create a Docker Container Using an Interactive Shell 16th May 2016 24,955k When you start a container in Docker from the Base image, Docker fetches the image and its parent image, and repeats the process until it reaches the Base image. Benefits of using PowerShell Docker over Docker CLI. Just postfix won't. To do this, run the system-switch-mail command and select postfix as the MTA. conf looks as follows: » cat /etc/resolv. I was recently helping a friend set up Octobox and noticed they very handily provide a pre-built docker-compose. Mount a Host Directory as a Data Volume In addition to creating a volume using the -v flag. Use a local repository as a private Docker registry to share Docker images across your organization with fine-grained access control. Start with Gitea and FreshRSS and get the tools to self-host almost anything. How do I install and setup Docker container on an RHEL 7 (Red Hat Enterprise Linux) server? How can I setup Docker on a CentOS 7? How to install and use Docker CE on a CentOS Linux 7 server? Docker is free and open-source software. You may be wondering why you’d ever want to use Docker containers to generate SSL certificates for the host. All integrated containers are available on Github and can be reviewed at any time. Content in the 'HowTos' hierarchy is written because its author believes it to work (one assumes) and to provide value as a reference. Using Docker Swarm for Deploying Node. If you use Docker for development this way, your production Dockerfile would copy the production-ready artifacts directly into the image, rather than relying on a bind mount. Understanding Docker "Container Host" vs. box setting. internal hostname to connect to your Docker host. Relying on the host MTA. com, into Docker Machine list of daemons, you need to use the generic driver. We're going to use VMware's Photon OS for this example because it's designed as a lightweight OS for hosting containers, and I deal with a lot of VMware environments. Docker containers use the host machine’s resources, but they have their own runtime environment. I have the gitlab/gitlab-ce:latest docker image and I want to configure E-Mails. The good people at Let's Encrypt also make an official client docker image available. js Microservices. #!/bin/sh set -e # This script is meant for quick & easy install via: # $ curl -fsSL https://get. Use the port you exposed in the docker run command. Using Docker within a Docker container In order to use Docker from within a Docker container, you need to bind-mount the Docker socket. 0" to the startup option of webpack-dev-server in the docker container in which server you want to access via http protocol by your browser. A local attacker could use this to cause a denial of service (crash) or possibly execute arbitrary code. But, I use a Mac laptop, as do most software engineers these days. hostname. We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. Quick postfix & dovecot config with virtual hosts (Ubuntu 16. Single host application deployments, automated testing, and local development are the most popular use cases for Docker Compose. If you continue browsing the site, you agree to the use of cookies on this website. Sharing your C drive with Docker for Windows when using Azure Active Directory. Docker creates three networks automatically on install: bridge, none, and host. Application containers, whether implemented using Docker, LXC, Rocket or another project, are gaining momentum. internal, but to really connect to a running host port using host. 1 as the host IP if you want to run multiple brokers otherwise the brokers won’t be able to communicate. CLI: Using the --add-host parameter with docker run. Using SMTP on Azure. Because you can access GPUs while using a Docker container, it's also a great way to link Tensorflow or any dependencies your machine learning code has so anyone can use your work. If using tags with tasks (described later as a means of only running part of a playbook), be sure to also tag your pre_tasks, post_tasks, and role dependencies and pass those along as well, especially if the pre/post tasks and role dependencies are used for monitoring outage window control or load balancing. I think host folder override into docker file system. We also share information about your use of our site with our social media, advertising and analytics partners. Perfect for setting up new mail exchangers (MX's) for your domain. You can connect to a docker-machine instance if you launch Visual Studio Code and have the Docker environment variables set in your environment or through the following VS Code settings: docker. A common use case for many users of Docker. But what if you need to connect to an. If you use Postfix, you could encounter issues with the service starting. 19) DOCKER_CONFIG The location of your client configuration files. Learn how to use a local registry with Docker to push images that contain proprietary code or confidential information that needs to remain private. Sign up run postfix with smtp authentication (sasldb) in a docker container. It helped to add such rules to the iptables of the host: iptables -A INPUT -i docker0 -p tcp -m tcp --dport 25 -j ACCEPT iptables -A INPUT -i docker0 -p tcp -m tcp --dport 80 -j ACCEPT. Both commands can either set or show the current host, domain or node name of the system. You should disable it (if possible) and move your ruleset to the DOCKER-USER chain, which is not cleared by a Docker service restart, instead. When new versions of PHP come out, you have to upgrade your entire development environment. Accepting all incoming connections which come from any Docker containers. All programmers are optimists -- Frederick P. Docker provides this same capability without the overhead of a virtual machine. I am giving multi-arch repo a try. Step 5: Add Hosts for Kubernetes cluster. with Systemd), the logs are in most cases logged through Syslog or other system logging mechanism. In this post I will explain how to deploy a Docker container host based on CentOS 7 in an automated way. He is able to use same code on internal machines withoit any issue. Docker for Mac / Docker for Windows. This has very serious security implications - namely, code inside the container can now run as root on your Docker host. Docker Beginner Tutorial 1 - What is DOCKER (step by step) Raghav Pal 348,430 views. 8) My host /etc/resolv. We have installed and configured Postfix as a send only SMTP server to send only outgoing mails from the docker container in the same server. Linux On Linux you can connect over the IP address listed in your docker0 network adapter. We create a container using docker run which we did using the busybox image that we downloaded. Docker Compose solves this problem by allowing you to use a YAML file to define multi-container apps. It was really easy for DNS or Web Server. Step 4 - Backup Redcap Database make sure you postfix with Redcap version number. Microsoft and Docker have been working together so that you'll have a great experience using Docker with. We will then use it to serve a simple web page from our home directory - all without the need to install a web server on our host. conf should make gethostbyname() first query /etc/hosts and then use any name servers configured in /etc/resolv. Each application comes with a docker-compose. conf looks as follows: » cat /etc/resolv. (docker host) will be able to be seen in the target (in the container). Docker allows applications to use the same Linux kernel as the system that they are running on. All containers are built using images (the central. Building good docker images. Docker has stabilized a lot since my early experiences as well. Dockerの勉強がてらに、今更感がありますが、Mastodonのインスタンスを立ててみました。 リバースプロキシや、サーバ証明書の自動更新をすべてDockerで 動かしたかったので以下の記事を参考にさせていただきました。 Docker. A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. To closely mirror this setup with Docker, we deploy 1 web container to each 3 hosts. It allows an IT administrator to manage a cluster of host systems as a resource pool. Collecting Docker infrastructure logs describes how to collect Docker logs (both host logs and container stdout) using syslog-ng running in a container and reading the hosts journal. In the given use case, I already had a PHP application running inside my Docker container being served by httpd (apache2). And when we remove the container data will be lost. This tutorial shows the steps to install an Ubuntu 18. Yes, an RPI Docker Host. (12) Use SQL Server from Python (13) Use SQL Server from PHP (14) Use SQL Server from Node. Like most applications, the need for sending the email came, ideally we should be using Amazon Web Services SES, but getting their approval was a pain in the @$$ and was taking Read more →. Simplify your cloud infrastructure with Linode's robust set of tools to develop, deploy, and scale your applications faster and easiert. I will use the WordPress Docker Compose example to test each of these options, as it has multiple containers, sets up links and networks between them, and is sufficiently complex for an example. I'd appreciate any critique of what I could do better. As of Docker v18. Step 1: Installing Apache2 and PHP7. We will then fix some of the issues that it warns us about. Install and Run Memcached as a service using docker Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. You might question why use Docker rather than VMware or Oracle's VirtualBox? While Docker utilizes the virtualization technology in the Linux kernel, it does not create virtual machines (in fact, if you run Docker on MacOS or Windows, you'll have to run it on a virtual machine). 04 or CentOS 7. A list of running containers can be seen using the docker ps command. Accessing the Docker Host Server Within a Container Jun 29 2014. Install Docker, then install Devstack and run stack. 0" to the startup option of webpack-dev-server in the docker container in which server you want to access via http protocol by your browser. Docker can then provision that remote system and your local docker tools can interface with it instead of your local machine. Docker Client for Windows can be used to manage Docker hosts running Linux containers today, and managing Windows Server Containers and Hyper-V Containers will be supported in the future to provide the same standard Docker Client and interface on multiple development environments. GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. with Jenkins), which seems fine at first, but they run into many “interesting” problems that can be avoided by bind-mounting the Docker socket into your Jenkins container instead. Project update. 5, you can upload your private Docker registry credentials to a secret store, then reference them in your app or pod definition. One of the benefits of using Docker is that the host OS doesn't matter. the second returns you to the host server’s command prompt. Docker Deployment on Azure | Microsoft Azure. Support is on a best-effort basis. Partner Portal. To fix this, you'll have to use an IPv4 loopback. Scanning container images on Red Hat Enterprise Linux Atomic Host v. What docker users need to know to move from Docker to Podman and Buildah and the advantages of doing so. # docker run --link=postfix-container my-awesome-app-that-needs-an-mta. You have a couple of options: You can access the Docker host by the container’s gateway. I set up postfix mail server in my linux host. Yet, the proper use of virtual machines is now widely understood and accepted even in environments where data security is important. Gmail accounts has very low sending limits. This should occur in the docker container. Docker Solution Briefs enable you to integrate the Docker Enterprise Edition container platform with popular 3rd party ecosystem solutions for networking, load balancing, storage, logging and monitoring, access management, and more. Use the operating system and Docker installation that fits your needs best. yml file through to configuring the Joomla. It is provided by the docker-latest RPM package. 99/mo! Host multiple sites affordably using Docker, Nginx…and SSD Nodes! Our Intel and SSD-backed servers and Tier-1 network connections give you the performance you need, for less. Install Docker Docker is required in order to work with Windows containers. AWS calls these virtual machines 'instances'. I'm going to use OpenVSwitch using VxLAN tunnels (or GRE tunnels) both are Linux kernel technologies that are true and tested (they are used in production for years). If Docker is already installed and ready to use, start Packetbeat in its own container. Like most applications, the need for sending the email came, ideally we should be using Amazon Web Services SES, but getting their approval was a pain in the @$$ and was taking Read more →. More info here. Create a Windows Container Using Docker. Mar 31, 2017. Docker Swarm. Why I don't use Docker much anymore 11 Mar 2015 17 minute read Update: The conclusion of this post talks about managing Docker kittens with Ansible; I no longer do that, but instead use Amazon ECS with Terraform. A Mail Transfer Agent (MTA) is the program which receives and sends out the email from your server, and is therefore the key part. On your Docker host, create a new directory called c:\iisdemo. Docker Solution Briefs enable you to integrate the Docker Enterprise Edition container platform with popular 3rd party ecosystem solutions for networking, load balancing, storage, logging and monitoring, access management, and more. Updated on December 22nd, 2017 in #docker. Some SMTP servers have delay period before processing takes place as an anti-spam feature, during which time synchronous method will block Redmine (10 seconds could be a default value, see also #11376 for more information). Docker Networking with Multiple Hosts. You will interact with Docker by using the client to send commands to the server. Now it is important to not have the same FQDN in myhostname as you use for your dockerized mailcow. conf when set to "files dns" and "order hosts,bind" in /etc/host. To build Postfix with TLS support, first we need to generate the make(1) files with the necessary definitions. To integrate hosts you access through ssh, such as my. Do not use localhost or 127. The primary purpose of Docker-in-Docker was to help with the development of Docker itself. This is all fine & dandy, and saves developers & ops engineers huge headaches, but I like to use Docker in a not-so-typical way. Sync'ing Host and Container Users in Docker. In this post, you'll build a. Catchpoint unveils Network Insights, an out-of-the-box network visibility solution. So I needed a Postfix image to act as a relay SMTP server for my application that was also in a Docker container. However, Docker does not take the. Sign up run postfix with smtp authentication (sasldb) in a docker container. internal hostname to connect to your Docker host. Note: There is a contributed gpiod project that runs the gpiod in its own container rather than on the host if required. 1 port 8888 - but not always. As of version 1. As of Docker v18. One of the things that makes Docker so useful is how easy it is to pull ready-to-use images from a central location, Docker's Central Registry. 1 port 8888 - but not always. Similar to the sidecar pattern, Docker Pipeline can run one container "in the background", while performing work in another. This API works for provisioning Docker on a local machine, on a virtual machine in the data center, or on a public cloud instance. Applications may use an internal one for speed or use the Glibc resolver. Useful debugging. The container must configure ssmtp to use postfix-container(or the name defined as the link) in the mailhub option in ssmtp. As Dynamics 365 Business Central or Microsoft Dynamics NAV developers we can spin up any version of the platform and app in minutes and use our favourite tools to work with it. I set up postfix mail server in my linux host. Based on Alpine Linux. Postfix packages are available under default repositories of Ubuntu operating systems. Docker benefits. And again, Ansible can be really helpful to put Docker on any remote machine. Create a Windows Container Using Docker. How do I configure Postfix MTA to send eMail using an external cloud-based SMTP server (with username: password) from a web server on Linux or Unix-like system? How do I configure an Ubuntu server and postfix as the relay server (smarthost)? You can configuring Postfix MTA to use as a Smarthost i.