1-19
Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring IPsec and ISAKMP
Configuring IPsec
•
Using Dynamic Crypto Maps, page 1-35
•
Providing Site-to-Site Redundancy, page 1-37
•
Viewing an IPsec Configuration, page 1-37
Understanding IPsec Tunnels
IPsec tunnels are sets of SAs that the ASA establishes between peers. The SAs specify the protocols and
algorithms to apply to sensitive data and also specify the keying material that the peers use. IPsec SAs
control the actual transmission of user traffic. SAs are unidirectional, but are generally established in
pairs (inbound and outbound).
The peers negotiate the settings to use for each SA. Each SA consists of the following:
•
IKEv1 transform sets or IKEv2 proposals
•
Crypto maps
•
Access lists
•
Tunnel groups
•
Prefragmentation policies
Understanding IKEv1 Transform Sets and IKEv2 Proposals
An IKEv1 transform set or an IKEv2 proposal is a combination of security protocols and algorithms that
define how the ASA protects data. During IPsec SA negotiations, the peers must identify a transform set
or proposal that is the same at both peers. The ASA then applies the matching transform set or proposal
to create an SA that protects data flows in the access list for that crypto map.
With IKEv1 transform sets, you set one value for each parameter. For IKEv2 proposals, you can
configure multiple encryption and authentication types and multiple integrity algorithms for a single
proposal. The ASA orders the settings from the most secure to the least secure and negotiates with the
peer using that order. This allows you to potentially send a single proposal to convey all the allowed
combinations instead of the need to send each allowed combination individually as with IKEv1.
The ASA tears down the tunnel if you change the definition of the transform set or proposal used to
create its SA. See the
“Clearing Security Associations” section on page 1-38
” for further information.
Note
If you clear or delete the only element in a transform set or proposal, the ASA automatically removes
the crypto map references to it.
Defining Crypto Maps
Crypto maps
define the IPsec policy to be negotiated in the IPsec SA. They include the following:
•
Access list to identify the packets that the IPsec connection permits and protects.
•
Peer identification.
•
Local address for the IPsec traffic. (See
“Applying Crypto Maps to Interfaces”
for more details.)
•
Up to 11 IKEv1 transform sets or IKEv2 proposals, with which to attempt to match the peer security
settings.
Summary of Contents for 5505 - ASA Firewall Edition Bundle
Page 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Page 61: ...P A R T 1 Getting Started with the ASA ...
Page 62: ......
Page 219: ...P A R T 2 Configuring High Availability and Scalability ...
Page 220: ......
Page 403: ...P A R T 2 Configuring Interfaces ...
Page 404: ......
Page 499: ...P A R T 2 Configuring Basic Settings ...
Page 500: ......
Page 533: ...P A R T 2 Configuring Objects and Access Lists ...
Page 534: ......
Page 601: ...P A R T 2 Configuring IP Routing ...
Page 602: ......
Page 745: ...P A R T 2 Configuring Network Address Translation ...
Page 746: ......
Page 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
Page 846: ......
Page 981: ...P A R T 2 Configuring Access Control ...
Page 982: ......
Page 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
Page 1062: ......
Page 1093: ...P A R T 2 Configuring Application Inspection ...
Page 1094: ......
Page 1191: ...P A R T 2 Configuring Unified Communications ...
Page 1192: ......
Page 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
Page 1334: ......
Page 1379: ...P A R T 2 Configuring Advanced Network Protection ...
Page 1380: ......
Page 1475: ...P A R T 2 Configuring Modules ...
Page 1476: ......
Page 1549: ...P A R T 2 Configuring VPN ...
Page 1550: ......
Page 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
Page 1966: ......
Page 2059: ...P A R T 2 System Administration ...
Page 2060: ......
Page 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Page 2099: ...P A R T 2 Reference ...
Page 2100: ......