Hi. I have Zimbra 8 OSE with muli-node configuration: ldap on server1.domain.com, mta on server2.domain.com and mailbox on server3.domain.com. And records: imap.domain.com and pop3.domain.com to server3.domain.com, smtp.domain.com to server2.domain.com. I need to install commercial sertificate on zimbra. What type of sert i can use and how many sert i must buy for all three dns record?