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First time configureing remote access VPN for 8.3 / 8.4 so the NAT and VPN commands are a bit diffrent for me.

Below is the VPN config and the coresponding NAT to NO NAT the IP space. If someone could have a look over it and let me know if I am missing anything. The network is 192.0.0.0 / 24 ha, not a typo.


crypto ikev1 enable outside

crypto ikev1 policy 10
encryption 3des
authentication pre-share
hash sha

access-list SPLIT-TUNNEL-VPN standard permit 192.0.1.0 255.255.255.0
access-list SPLIT-TUNNEL-VPN standard permit 192.0.0.0 255.255.255.0

group-policy REMOTE-VPN-GP internal
group-policy REMOTE-VPN-GP attributes
vpn-tunnel-protocol ikev1
address-pools value REMOTE-VPN-POOL
split-tunnel-policy tunnelspecified
split-tunnel-network-list value SPLIT-TUNNEL-VPN
dns-server value 192.0.0.201

tunnel-group REMOTE-VPN-TG type remote-access
tunnel-group REMOTE-VPN-TG general-attributes
default-group-policy REMOTE-VPN-GP
authentication-server-group LOCAL

tunnel-group REMOTE-VPN-TG ipsec-attributes
ikev1 pre-shared-key **********

ip local pool REMOTE-VPN-POOL 192.0.1.1-192.0.1.100 mask 255.255.255.0

crypto ipsec ikev1 transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
crypto dynamic-map OUTSIDE-DYNMAP 65535 set ikev1 transform-set ESP-3DES-SHA

crypto map OUTSIDE_MAP 65535 ipsec-isakmp dynamic OUTSIDE-DYNMAP
crypto map OUTSIDE_MAP interface outside

//No NAT subnet

object network INSIDE_LAN
subnet 192.0.0.0 255.255.255.0

object network VPN_LAN
subnet 192.0.1.0 255.255.255.0

nat (inside,outside) source static INSIDE_LAN INSIDE_LAN  destination static VPN_LAN VPN_LAN

or would I do this for the no nat:

nat (inside,outside) 1 source static any any destination static VPN_LAN VPN_LAN

My NAT is currently set up as:

object network LAN_NAT
subnet 192.0.0.0 255.255.255.0
nat (inside,outside) dynamic interface

1 Answer 1

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If 192.0.0.0/24 is your inside interface/LAN then what is 192.0.1.0/24?

You have given the object name of VPN_LAN to the 192.0.1.0/24 subnet? However, you define the remote-access VPN address pool as 10.1.2.140-10.1.2.145. The addresses assigned to the client VPN adapters will be in the range of 10.1.2.140-10.1.2.145.

I am going to assume that 192.0.1.0/24 is not needed and that your inside is 192.0.0.0/24 and your VPN client adapters will have IP's pulled from the 10.1.2.140-10.1.2.145 pool -- you may just want to make this 10.1.2.0/24 -- however I will continue with your existing pool.

You can configure your inside outbound dynamic interface PAT setup with the following. You have created another LAN_NAT object when you can define your dynamic interface PAT right in the INSIDE_LAN object -- they appear in two different parts of the configuration (subnet definition and object NAT) but are (and can) still defined in the same object.

object network INSIDE_LAN
 subnet 192.0.0.0 255.255.255.0
 nat (inside,outside) dynamic interface

Below is a network object created that represents the IP block that is the pool. Does not redefine the pool itself as that is ip local pool.

object network RAVPN_POOL
 subnet 10.1.2.0 255.255.255.0   ! adjust this and pool itself to meet needs

Configure your identity NAT (no nat) as follows -- not in an object, but a twice NAT.

nat (inside,outside) source INSIDE_LAN INSIDE_LAN destination static RAVPN_POOL RAVPN_POOL description [[ Inside to RA Identity NAT ]]

Assuming I understand your setup you can then rid yourself of the LAN_NAT and VPN_LAN objects and the 192.0.1.0/24 entry in the SPLIT-TUNNEL-VPN ACL.

no access-list SPLIT-TUNNEL-VPN standard permit 192.0.1.0 255.255.255.0
no object network LAN_NAT
no object network VPN_LAN

There are some additional things to be considered on your P1/IKE policy as well -- 3DES/MD5 in P1 when you have P2 defined as 3DES/SHA is fine, but slightly odd.

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  • Thanks for the great write up. I actually had the wrong IP range in my VPN pool. It was supposed to be 192.0.1.1-192.0.1.100. I also change the P1 to SHA as well. It looks like with the VPN range correction I should be good, correct?
    – evolvd
    Nov 3, 2011 at 9:28
  • @evolvd Just ensure that whatever range you choose you have the pool set correctly, the NAT Identity set correctly, and split-tunnel-network-list ACL set correctly. Your P1, P2/crypto map, and Tunnel-Group look fine.
    – Weaver
    Nov 5, 2011 at 15:19

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