Cisco ASA site to site VPN with NAT

Posted on 2009-07-05
Last Modified: 2012-05-07
Hi, I know this I am sure has been asked a dozen times and I have found what looks like what I want but have been unable to make it work so I am just going to put on here what someone asked me to do. First off I am very new to Cisco equipment I got the ASA setup and working but then they want this and I am not sure how to do it exactly. Here is what  they asked.

Our endpoint is: their outside IP
Our network is: (

will need to make ACL from A.A.A.10  to hosts192.168.50.83,,, and

clinic will need to NAT interesting traffic to A.A.A.A  

Phase 1

Authentication: Pre-Shared
Encryption: 3DES
Hash: SHA
DH: 1
Lifetime: 86400 sec
Pre-shared Key: Big key

ESP encryption 3DES
ESP authentication
Lifetime 28800

I think they left off something with the ESP authentication but I dont know. The internal network  is
Thanks for all the help!
Jarrid Graham
Question by:jarridgraham
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LVL 13

Expert Comment

ID: 24785696

Here is a great document to help explain the pieces need to get what you want to do working.

With that said. What device is on the other end of the tunnel? And if you care to share your configs we can look through them together.



Author Comment

ID: 24785804
    OK here is the config so far. If I set up the lan to lan VPN without screwing with the NAT. I can go to another machine  and try to ping the network and I see the tunnel start to come up, gets by Phase 1 but has a Phase 2 problem. something about Invalid ID Info (18). I am not sure what that refers to. When I mess with the NAT and change the VPN settings it never tries any more.
    I have no idea what hardware is on the other end, all I am told is it is set up right as uasual, we have done this a million times kind of stuff. Last time I spent a week working on a simple VPN setup that I could not get to work and found out they had a IP config error on their end.
    Should the VPN come up without the NAT but not be able to pass traffic or will that have an effect on the VPN where it just fails at the Phase2 point.


: Saved
ASA Version 7.2(4)
hostname ciscoasa
domain-name default.domain.invalid
enable password  encrypted
passwd  encrypted
interface Vlan1
 nameif inside
 security-level 100
 ip address
interface Vlan2
 nameif outside
 security-level 0
 ip address myoutoutsideIP
interface Ethernet0/0
 switchport access vlan 2
interface Ethernet0/1
interface Ethernet0/2
interface Ethernet0/3
interface Ethernet0/4
interface Ethernet0/5
interface Ethernet0/6
interface Ethernet0/7
ftp mode passive
dns server-group DefaultDNS
 domain-name default.domain.invalid
access-list outside_access_in extended permit icmp any any
access-list outside_access_in extended permit ip any any
access-list VPN1 extended permit ip A.A.A.A
access-list INSIDE_nat_static extended permit ip
access-list outside_1_cryptomap extended permit ip A.A.A.A
access-list inside_access_in extended permit ip any any
pager lines 24
logging enable
logging asdm informational
mtu inside 1500
mtu outside 1500
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-524.bin
no asdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1
static (inside,outside) tcp interface 3389 3389 netmask
static (inside,outside) A.A.A.A  access-list INSIDE_nat_static
access-group inside_access_in in interface inside
access-group outside_access_in in interface outside
route outside 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
http server enable 500
http outside
http inside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
crypto dynamic-map outside_dyn_map 20 set pfs group1
crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-SHA
crypto map outside_map 1 match address outside_1_cryptomap
crypto map outside_map 1 set peer TheiroutsideIP
crypto map outside_map 1 set transform-set ESP-3DES-SHA
crypto map outside_map 65535 ipsec-isakmp dynamic outside_dyn_map
crypto map outside_map interface outside
crypto isakmp enable outside
crypto isakmp policy 10
 authentication pre-share
 encryption 3des
 hash sha
 group 1
 lifetime 86400
telnet timeout 5
ssh outside
ssh timeout 5
console timeout 0
dhcpd auto_config outside
dhcpd address inside

tunnel-group TheiroutsideIP type ipsec-l2l
tunnel-group TheiroutsideIP ipsec-attributes
 pre-shared-key *
class-map inspection_default
 match default-inspection-traffic
policy-map type inspect dns preset_dns_map
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns preset_dns_map
  inspect ftp
  inspect h323 h225
  inspect h323 ras
  inspect rsh
  inspect rtsp
  inspect esmtp
  inspect sqlnet
  inspect skinny
  inspect sunrpc
  inspect xdmcp
  inspect sip
  inspect netbios
  inspect tftp
service-policy global_policy global
prompt hostname context
: end
asdm image disk0:/asdm-524.bin
no asdm history enable

LVL 13

Expert Comment

ID: 24786481
Without NAT the VPN will come up because of this rule:
access-list outside_1_cryptomap extended permit ip A.A.A.A

but traffic will not pass without the no noat.

You have this:

nat (inside) 1

but you need to create a nonat acl and then add this:

nat (inside) 0 access-list nonat

Log into the asdm and make sure logging is turned on an post the errors for further help. As until you get phase 2 corrected you will be dead in the water.



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Author Comment

ID: 24791049
OK, I just cleaned it up and just went with a stright VPN connection here is the error log. I suspect they may have something wrong on their end but I have to be able to prove it.
LVL 13

Expert Comment

ID: 24793964
access-list outside_1_cryptomap extended permit ip A.A.A.A

Please confirm the subnets on this crypto acl.

A.A.A.A should be your local subnet which appears to be should be the other side

Let me know what is where.



Author Comment

ID: 24807271
Yes there is a line like that, I would guess that is how it decides on that to build the VPN for. I just wonder if the VPN should come up with out the NAT magic or if they may have something wrong on their end  with that Phase 2 error.
LVL 13

Expert Comment

ID: 24807444
The error you gave me means one end has a problem with there crypto acl.

What is the remote subnet and mask??
What is the local subnet and mask?



Author Comment

ID: 24807849
OK I must be thinking about this all wrong.  OK here is what I want to do, my local network is and their local is and they want me to NAT my traffic so it looks like is comes from lets say I guess what I dont get is how to even know if the NAT statements actually are doing anything.
LVL 13

Expert Comment

ID: 24808641
my local network is and their local is and they want me to NAT my traffic so it looks like is comes from lets say --> no clue how you would accomplish that. I can help you make the vpn work but a vpn is per-nat so no clue how that would ever work. If you want to close this question and start another I have no objections.



Author Comment

ID: 24810293
Well maybe you can still help, I did get the NAT stuff to do what I want but I still have the same error but for some reason there is a lot more debug info that I am attaching.
LVL 13

Accepted Solution

3nerds earned 500 total points
ID: 24817497
Your phase 2 still isn't coming up. What is and is not working?


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