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For further isolation you may have purchased an additional IP address. For example run Apache on your host using port 80 and then also run Apache inside one of your containers also requiring port 80. Since it is not possible to have port 80 twice on the same IP you opt to purchase a second IP.
In most hosting services this is not expensive, but they will likely not give you a dedicated network card. In this example we purchase an additional static IP from the hosting company and use the same network card as the host.
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