Note: The docker tag  command accepts either zCX IP name or an IP address. Important: If you use IP address in your zCX Docker configuration, ensure you also use IP address when use docker tag  to manage your images. The same requirement applies to the use of the zCX IP name. 

Example:  If you use sc74cn03.pbm.ihost.com  in Docker settings in your zCX, use this address every time that you use docker tag , docker pull, and docker push  commands. 

3. Click Next  until you reach the windows where you review instructions. 

4. Click Finish . 

5. Select Step 3 of the workflow ( Start IBM zCX appliance reconfiguration ) and select to Actions > Perform . When requested, choose to run the rest of the workflow in automated mode. 

The workflow halts as it reaches the steps where you stop and restart the zCX instance. You must manually stop and restart the instance to finish the workflow. 

When the instance comes up again, connect through SSH and complete the steps in the next section. 

After you confirm that the zCX settings for a secure registry are correct applied, complete the steps in the next section. Notice that you need a Windows or Linux system with internet access to be able to download Docker images from Docker Hub. In our case, we installed a SuSE Linux Enterprise Server 12, and attached it to a network that had internet access. 

## 6.5.1 When zCX appliance is behind a firewall 

In some organizations, the zCX instances might not have direct internet access. Therefore, the Docker client that runs on the zCX cannot pull Docker images from Docker Hub. 

In such cases, you have options to download these images by using a laptop or any other system that has access to internet. In fact, you download the images from a host that has access to internet and then copy these images to a zCX instance. 

These are the requirements to deploy a secure private registry behind a firewall. 

GLYPH<SM590000> One system (container or stand-alone) with internet access 

GLYPH<SM590000> Docker package installed (Docker client pulls images from Docker Hub) 

Later in this section, we show how to download images by using a Linux instance and load them onto the zCX appliance. However, the procedure can be used on a computer that runs Windows or Macintosh if you have Docker client installed there. 

This publication does not cover Docker installation for Windows, Macintosh, and other Linux distributions. Installation for those platforms is described at the following web pages: 

GLYPH<SM590000> For Windows: https://docs.docker.com/v17.12/docker-for-windows/install/ 

GLYPH<SM590000> For Linux: https://docs.docker.com/v17.12/install/#time-based-release-schedule 

GLYPH<SM590000> For Ubuntu: https://docs.docker.com/v17.12/install/linux/docker-ce/ubuntu/ 

GLYPH<SM590000> For Macintosh: https://docs.docker.com/v17.12/docker-for-mac/install/ 

The following steps describe deployment of a private secure private in SuSE Linux. The procedure is very similar for other operating systems. 

