Purpose: Add IPsec policies to configure the IKE encryption and authentication algorithms used for site-to-site VPN connections.
Location: Gateways > (gateway name) > Site-to-Site VPN > Policies
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Click Add.
The Add/Edit IPSec Policy window opens.
- Specify a name for the new IPsec policy.
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Select the IKE encryption algorithm from
the drop-down list box.
Note:
The Digital Encryption Standard (DES) is a 64-bit block algorithm that uses a 56-bit key. The Advanced Encryption Standard (AES) is a private key algorithm supporting key lengths from 128 to 256 bits and variable-length blocks of data.
Option Description 3DES
Triple-DES, in which plain text is encrypted three times by three keys.
AES 128
A 128-bit block Cipher Block Chaining (CBC) algorithm that uses a 128-bit key.
AES 192
A 128-bit block Cipher Block Chaining (CBC) algorithm that uses a 192-bit key.
AES 256
A 128-bit block Cipher Block Chaining (CBC) algorithm that uses a 256-bit key.
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Select the IKE authentication
algorithm value from the drop-down list box.
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MD5—Message Digest (version 5) hash algorithm (on one-way hash function) developed by RSA Data Security, which is intended for digital signature applications, where a large file must be compressed in a secure manner before being encrypted with a private key/public key algorithm.
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SHA1—Secure Hash Algorithm 1, which produces a 160-bit message digest. The large message digest provides security against brute-force collision and inversion attacks.
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SHA-256—Secure Hash Algorithm 2 with a 256-bit digest. SHA2 digests provide higher security against brute-force collision and inversion attacks.
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SHA-512—Secure Hash Algorithm 2 with a 512-bit message digest. The largest message digests provide the highest security against brute-force collision and inversion attacks.
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- Select the IKE SA lifetime value (in hours, maximum 24) from the drop-down list box (1-24). It specifies the length of time that the negotiated key will stay effective.
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Select the IKE DH group value from the
drop-down list box that are supported by secure gateways.
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Group2: MODP—1024 bits (default)
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Group5: MODP—1536 bits
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Group14:MODP—2048 bits
The above groups refer to the Diffie-Hellman key computation (also known as exponential key agreement) that is based on the Diffie-Hellman (DH) mathematical groups supported by a security gateway for IKE and IPsec Security Association (SA).
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Select the IPsec encryption value from the
drop-down list box.
- No encryption—Do not use an encryption algorithm.
- 3DES
- AES 128
- AES 192
- AES 256
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Select the IPsec authentication algorithm
value from the drop-down list box.
- MD5
- SHA1
- SHA-256
- SHA-512
- Select the IPsec lifetime value (in hours, maximum 24) from the drop-down list box (1-24).
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Select the IPsec PFS group value from the
drop-down list.
- None
- Group2: MODP
- Group5: MODP
- Group14:MODP
- Click Save.