- Private network:
- Private Network (PN)
= a
secure communication network
usually own by a coorporation
and
built with
leased telecommunication lines
- Communication on a private network is very hard to tap (eaves drop)
Graphically:
(Commication is secure because the leased line cannot be easily tapped)
- Private Network (PN)
= a
secure communication network
usually own by a coorporation
and
built with
leased telecommunication lines
- Secure IP: (IPsec)
- Secured IP communication = a secure communication built on top of the (unsecure) IP network
- Graphically:
- How to prevent
eaves dropping
and achieve privacy protection:
- Encrypt the inner IP packet
- Transmit the encrypted IP packet securely with the outer IP packet
- Graphically:
- Packet format used
in Secure IP:
- Tunnel setup:
Note:
- The optional processing
used before the
IP packet is
encapsulated is:
- Encryption (and authentication)
- The optional processing
used before the
IP packet is
encapsulated is:
- How an
(plain) IP packet will be
transmitted:
- Host 2.2.2.4 transmit
a plain IP message to
7.7.7.9:
- The virtual interface entry
will cause the
IP packet to be
encrypted and
encapsulated:
The other IP packet will use the packet code 50 to indicate it is a IPsec encapsulation
- The encapsulated IP packet will
be sent to
the router 4.4.4.1:
- When the
encapsulated IP packet
arrives at 4.4.4.1, the
router detects
its own IP address and
de-encapsulate
The router will decrypt the inner packet because the outer code = 50
- The de-crypted IP packet is
forwarded further:
- Host 2.2.2.4 transmit
a plain IP message to
7.7.7.9:
- IPsec also provides
an authentication mechanism that
I have omitted
- External material with the complete description of IPsec: click here