Site-to-Site IPSec VPN using GRE Configuration

Site-to-Site IPSec VPN using GRE Configuration

• Cisco IPSec VPN Topology
  
  
  
  
• Configuration Settings Overview
  
  
  1. ping / traceroute
     Between HQ and Branch1
     Between HQ and Bransh2
     Between Branch1 and Branch2
     
     
  2. Segment of each site
     HQ : 192.168.0.0/20
     Branch1 : 192.168.16.0/20
     Branch2 : 192.168.32.0/20
     
     
  3. Router HQ1,BR11,BR21 IPSec Configuration

     3.1 IKE Policy
       3.1.1 HQ
         iskakmp policy 10
           encryption     : des
           hash           : md5
           authentication : pre-share
           DH group       : group 1
     
         isakmp policy 20
           encryption     : 3des
           hash           : md5
           authentication : pre-share
           DH group       : group 2
     
         isakmp policy 30
           encryption     : aes
           hash           : sha
           authentication : pre-share
           DH group       : group 2
     
         pre-shared key   : cisco123(address: 20.0.0.2)
         pre-shared key   : cisco456(address: 30.0.0.2)
     
       3.1.2 Branch1
         isakmp policy 10
           encryption     : 3des
           hash           : md5
           authentication : pre-share
           DH group       : group 2
     
         pre-shared key   : cisco123(address 10.0.0.2)
     
       3.1.3 Branch2
         isakmp policy 10
           encryption     : aes
           hash           : sha
           authentication : pre-share
           DH group       : group 2
     
         pre-shared key   : cisco456(address 10.0.0.2)
     
     3.2 IPSec Transform Set
       3.2.1 HQ
         ipsec transform-set Trset10
           protocol   : esp
           encryption : des
           hash       : md5-hmac
     
         ipsec transform-set Trset20
           protocol   : esp
           encryption : 3des
           hash       : md5-hmac
     
         ipsec transform-set Trset30
           protocol   : esp
           encryption : aes
           hash       : sha-hmac
     
       3.2.2 Branch1
         ipsec transform-set Trset10
           protocol   : esp
           encryption : 3des
           hash       : md5-hmac
     
       3.2.3 Branch2
         ipsec transform-set Trset10
           protocol   : esp
           encryption : aes
           hash       : sha-hmac
     
     3.3 Crypto Map
       3.3.1 HQ
         crypto map ToBR 10 ipsec-isakmp
           set peer 20.0.0.2
           set transform-set Trset20
           match address 101
         crypto map ToBR 20 ipsec-isakmp
           set peer 30.0.0.2
           set transform-set Trset30
           match address 102
     
       3.3.2 Branch1
         crypto map ToHQ ipsec-isakmp
           set peer 10.0.0.2
           set transform-set Trset10
           match address 100
     
       3.3.3 Branch2
         crypto map ToHQ ipsec-isakmp
           set peer 10.0.0.2
           set transform-set Trset10
           match address 100
     
     3.4 IPSec VPN access-list
       3.4.1 HQ
         HQ To Branch1
           access-list 101 permit gre host 10.0.0.2 host 20.0.0.2
     
         HQ To Branch2
           access-list 102 permit gre host 10.0.0.2 host 30.0.0.2
     
       3.4.2 Branch1
         Branch1 To HQ
           access-list 100 permit gre host 20.0.0.2 host 10.0.0.2
     
       3.4.3 Branch2
         Bracnch2 To HQ
           access-list 100 permit gre host 30.0.0.2 host 10.0.0.2
     

• Dynagen Config File / Router Config

  1.  Dynagen .net file
  
  2.  HQ1
  
  3.  HQ2
  
  4.  HQHOST
  
  5.  BR11
  
  6.  BR12
  
  7.  BR1HOST
  
  8.  BR21
  
  9.  BR22
  
  10. BR2HOST
  
  11. R1
  

• show command

  HQ1 :
    sh crypto isakmp sa
    sh crypto engine connections active
  BR11 :
    sh crypto isakmp sa
    sh crypto engine connections active
  BR21 :
    sh crypto isakmp sa
    sh crypto engine connections active
  
  1.  HQ1
  
  2.  BR11
  
  3.  BR12