Change of hostname in postfix
I have changed the hostname and domain that the ISPConfig server is using, adding a second IP address for it to use. With help from here, getting it to run on a different IP was no problem (I still can't change the port, but that's another matter)
Today's snag is the mail server. When people connect to it, it is giving the old hostname in its greeting instead of the new one.
I guess that I can change the content of /etc/postfix/main.cf, amending the line that says
myhostname = servername.com
Would this be OK, or would ISPConfig overwrite my changes from somewhere else?
What I'm concerned about is that this would probably mess up the certificates connected with the postfix installation. Does this matter? If so, how do I fix it?