Jul 28

How to Configure a Cisco ASA Site-to-Site IPSec VPN

This article will explain how to configure a Site-to-Site IPSec VPN using Cisco ASA 55XX’s using IKEV1.  My example below shows how to configure VPN’s between 3 sites but can be modified for the following scenarios without much explanation:

  • site-to-site VPN between 2 sites (Just remove SiteC… duh!)
  • site-to-site to 3+ sites (just follow the example and modify for a N+1 sites.  If You’re doing more than 3 sites, you may wish to look at a hub and spoke model to simply the network and backups, etc)
  • Hub and spoke VPN, where 2 remote offices only connect to a main office (If SiteA is the Hub, on SiteB remove the SiteC configuration, on SiteC remove the SiteB configuration, etc…)

Overview

Network Diagram

ASA_Multi_Site-to-site_IPSEC_VPN

Network Diagram

Phase 1 Settings

Attribute Value
Authentication Preshared Keys
Encryption 3DES
Hash MD5
DH Group Group 2
Lifetime 86400 seconds

Phase 2 Settings

Attribute Value
Mode Tunnel
Encryption 3DES
Hash SHA-1
PFS Enabled
Lifetime 86400 seconds

Configure SiteA

 

Configure SiteB

Configure SiteC

 

Further Info

I would suggest using IKEV2 for a Site-to-Site VPN, and I’ll outline the steps a in future article once I get time to write it up…. Stay tuned!