Do WCF Services have to have a MetaDataExchange endpoint for each service or can I have just one?

Question

If my WCF Configuration file has two services, lets says LoginService and RegistrationService, do they both have to have their own MetaDataExchange endpoint or can I just have one MetaDataExchange endpoint and keep it outside the service element:

<services>
<service name="a">
<endpoint binding="mexHttpBinding" />
</service>
<service name="b">
<endpoint binding="mexHttpBinding" />
</service>
<services>

Or is this valid as well:

<services>
<service name="a">
</service>
<service name="b">
</service>
<endpoint binding="mexHttpBinding" />
<services>

Answer 1

The first one.

When you add a service reference, it is for a service not for all services on a server.