- Method of translation of private IP to public IP address
- In order to
communicate with internet we must have registered public IP address
- It can be
configured on Routers, firewalls, servers
Public IP:
- Used on public
network (INTERNET)
- It recognized on
internet
- It is given by the
service provider (from IANA)
- Globally unique
- Need to pay to
service provider (or IANA)
- It should be
registered
Private IP:
- It used with the
LAN or within the organization
- It not recognized
on internet
- It is given by the
administrator
- It only unique
within the network or organization
- It free of cost
- No need to
register
Types of NAT:
- Static NAT
- Dynamic NAT
- Port Address
Translation (PAT)
Static NAT:
- One to one mapping
and it should be done by the administrator manually
- Every private IP
needs one registered public IP address (one : one)
Dynamic NAT:
- One to one mapping
and it will be done automatically by NAT device
- For every private
IP needs one registered public IP address (one : one)
Port Address
Translation (Dynamic NAT overload)
- Thousands of
private users – use single public IP address
- It uses port
numbers to map to single public IP to differentiate each connections
- PAT is the real
reason we haven’t run out of valid IP address on internet
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