SSL Certificate for e-mail: do I need wildcard?

Hi there,
I would like to use a SSL Certificate so my customers can securely connect with my mailserver (instead of a self-signed certificate like now).
The mailserver is also webserver, and listens to a FQDN like:
The mailserver I provide my clients is (which points to the IP of with a DNS A-Record)

My question is now: if I take a single SSL-certificate (so no wildcard) for, will this be enough to also secure (as the FQDN of the server is and this will have a valid SSL) or do I need a wildcard certificate for * because the mail-clients are being told to connect to
Or, if you like, the actual question is: for SMTP (not HTTP!) do I need a SSL-certificate for the hostname that is configured in the mail-client or is it sufficient to have a SSL-Certificate for the FQDN of the server (which is also what the server sends (EHLO))

Thanks in advance, tried for ages to find out but couldn’t find something really answering my question until now.

SSL is host based if you take SSL for then it will only secure
You will have to take a separate SSL for
If you buy Wildcard SSL then it will work for *