DIFFERENCE BETWEEN MIP,VIP AND DIP IN JUNIPER

Juniper ScreenOS platform supports Source NAT as well as Destination NAT and hence utilizes following terminologies – MIP , VIP and DIP.

The abbreviation for each term is –

Mapped IP (MIP)
Virtual IP (VIP)
Dynamic IP (DIP)

An MIP maps one external IP address to one internal IP address and does not alter the port information. A VIP maps one external IP address and one external port to a multiple number of possible IP addresses and ports. It can also translate external port to same or different internal port. DIP can enable policy-based NAT, and NAT, before VPN encapsulation; in which overlapping private IP addresses exist in a VPN network. Notable is that VIP and DIP is unidirectional whereas MIP is bidirectional.

Below comparison table will differentiate between MIP,VIP and DIP terms used in ScreenOS –

PARAMETER	MIP	VIP	DIP
Philosophy	A one-to-one mapping of one address to another. a	A virtual IP (VIP) address maps traffic received at one IP address to another address based on the destination port number in the TCP or UDP protocol s	A dynamic IP (DIP) address pool is a range of IP addresses from which the device can dynamically take addresses to use when performing NAT on the source IP address of outgoing or incoming IP packets.
NAT Type	Destination NAT and Source NAT	Destination NAT	Source NAT
Usage	Static NAT to/from Servers	Outgoing NAT instead of using egress Interface IP	Port forwarding to Servers
Port usage	No	Yes	Yes
Mapping Type	One-to-One	One-to-Many	One-to-Many and Many-to-One
Flow Direction	Bidirectional.Traffic can be initiated from inside source or Outside Source	Unidirectional.Traffic can be initiated from inside source only for VIP to take effect	Unidirectional.Traffic can be initiated from outside source only for DIP to take effect