Multiple SMTP domains

On single exchange 2010 server we have  users who use multiple SMTP domains for email.
1.)So how is  autodiscovey configured so that  it works for all the SMTP domains.
2.) do i need to have multiple DNS records for autodiscover  Ex: autodiscover.domain1.com , autodiscover.domain2.com etc
3.) In the SAN certificate do I need to include autodiscover.domain1.com ,
autodiscover.domain2.com

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Regards Malli Boppe