What are the DNS requirements for IPOCC?

[sedge]

During the installation and when using the Configuration spreadsheet there is the requirement to enter the IP address of a DNS server.

What records are required on the DNS server for IPOCC to function?

Thanks

Steve

[sedge]

I have been advised that DNS entries are required for IPOCC to resolve email and chat.

i.e. DNS SRV records required on the DNS server for MX and XMPP