SharePoint 2010 missing host header?

I am trying to resolve some of the problems I am having in my environment and I think it is all related to a possible host header misconfiguration.

When I run the following code in my environment:

$wa = get-spwebapplication “http://mywebapp”
$iissettings = $wa.GetIisSettingsWithFallback("Default")
$iissettings.serverbindings

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I get the following result:

HostHeader   Port UpgradedPersistedProperties             
----------   ---- ---------------------------             
              80                                         

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I guess that suggests that my host header is missing? How do I fix it?