Zoho IP addresses used to access a customer's IMAP and STMP ports

Zoho IP addresses used to access a customer's IMAP and STMP ports

I am trying to setup the IMAP and SMTP integration for a customer. IMAP isn't enabled by their IT company. They won't enable it until I can tell them the range of IP addresses (belonging to Zoho) that would be accessing the IMAP and SMTP port because they don't want to expose those ports to the world - is this something that you give out? 
Or, are you close to releasing a true Exchange connector that doesn't required IMAP and SMTP?