cisco ASA: ipsec example

Tagged as cisco, ASA, IPSEC, vpn

Written on 2016-02-28 14:33:03

I fear I will need something like that soon, so here's a dump I found on google somewhere else: (None of the following is from me! But from here)

Table 1 Preconfiguration Checklist: ISAKMP/Phase-1 Attributes

Attribute   Value
Encryption  AES 128-bit
Hashing SHA-1
Authentication method   Preshared keys
DH group    Group 2 1024-bit field
Lifetime    86,400 seconds

We will use main mode rather than aggressive mode for negotiation. IPsec Phase 2 attributes are used to encrypt and decrypt the actual data traffic.

Table 2 Preconfiguration Checklist: IPsec/Phase-2 Attributes

Attribute   Value
Encryption  AES 128-bit
Hashing SHA-1
Lifetime    28,800 seconds4,608,000 kB
Mode    Tunnel
PFS group   None

Now that we have determined what Phase 1 and Phase 2 attributes to use, we’re ready to configure IPsec. We assume that all IP addresses are already configured and basic connectivity exists between Cisco ASA and pfSense firewall.

ASA Configuration

! IPsec ISAKMP Phase 1

crypto ikev1 policy 1
authentication pre-share
encryption aes
hash sha
group 2
lifetime 86400
crypto ikev1 enable outside

tunnel-group type ipsec-l2l
tunnel-group ipsec-attributes
ikev1 pre-shared-key Cisc0

! IPsec Phase 2

crypto ipsec ikev1 transform-set pfSense-AES128SHA esp-aes esp-sha-hmac
access-list outside_cryptomap_10 remark ACL to encrypt traffic from ASA to pfSense
access-list outside_cryptomap_10 extended permit ip
crypto map outside_map 10 match address outside_cryptomap_10
crypto map outside_map 10 set peer
crypto map outside_map 10 set ikev1 transform-set pfSense-AES128SHA
crypto map outside_map interface outside

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