Black Box ET0010A User Manual
Policy Concepts
EncrypTight User Guide
183
TIP
Network connectivity problems can prevent new keys from being distributed to the PEPs before the old
keys expire. If you experience problems of this nature, see
keys expire. If you experience problems of this nature, see
for suggested workarounds to prevent interruptions.
Policy Types and Encryption Methods
The type of policy specifies the action applied to packets that match the protocol and networks included
in this policy. You can choose from the following types:
in this policy. You can choose from the following types:
●
Drop - drops all packets matching this policy.
●
Bypass - passes all packets matching this policy in the clear.
●
IPSec - encrypts or decrypts all packets matching this policy. (For Layer 2 Ethernet policies, this
option is Encrypt.)
option is Encrypt.)
The following topics describe how traffic is protected in an encryption policy:
●
●
Encapsulation
To provide encryption and authentication, the PEPs use the EncrypTight Encapsulating Security Payload
protocol (CE-ESP). CE-ESP is Black Box’s packet encapsulation protocol that is based on the IPSec ESP
protocol standards.
protocol (CE-ESP). CE-ESP is Black Box’s packet encapsulation protocol that is based on the IPSec ESP
protocol standards.
Layer 2: Ethernet payload encryption
In Layer 2 policies, the CE-ESP protocol preserves the original Ethernet header information and encrypts
only the Ethernet payload, as shown in
only the Ethernet payload, as shown in
Figure 67
Ethernet frame encryption
Layer 3: IPSec Tunnel mode with original IP header preservation
In Layer 3 IP policies, a copy of the original IP header is used as the outer header and the original header
and payload are encrypted, as show in
and payload are encrypted, as show in
.
Figure 68
IP packet encryption
Layer 4: IPSec Transport mode for Layer 4 payload encryption
ETEP PEPs have an option to encrypt only the Layer 4 payload. The TCP and UDP header information
remains in the clear, as shown in
remains in the clear, as shown in
. All other Layer 4 headers are encrypted.