Solved

Conditional PAT/NAT on Cisco ASA

Posted on 2009-05-07
2
1,604 Views
Last Modified: 2013-11-16
I have to create an L2L tunnel and PAT the internal network 10.x.x.x to a single address 172.19.1.14 to access a remote site which has a subnet 10.38.49.0/25. The PAT address is dictated by the user at the remote end.

The following are bits from the ASA configuration
access-list in_inside line 1 extended permit ip 10.0.0.0 255.0.0.0 10.38.49.0 255.255.255.128 (hitcnt=43)
!
access-list CONDITIONAL_NAT; 1 elements
access-list CONDITIONAL_NAT line 1 extended permit ip 10.0.0.0 255.0.0.0 10.38.49.0 255.255.255.128 (hitcnt=0)
!
access-list 106 line 1 extended permit tcp host 172.19.1.14 10.38.49.0 255.255.255.128 (hitcnt=0)
access-list 106 line 2 extended permit udp host 172.19.1.14 10.38.49.0 255.255.255.128 (hitcnt=0)
!
crypto map YYY-Crypto-Map 30 match address 106
crypto map YYY-Crypto-Map 30 set pfs group5
crypto map YYY-Crypto-Map 30 set peer x.x.x.x
crypto map YYY-Crypto-Map 30 set transform-set tertiary
!
crypto map YYY-Crypto-Map 100 ipsec-isakmp dynamic YYY-Dynamic-Map
!
crypto map YYY-Crypto-Map interface Outside
crypto isakmp enable Outside
crypto isakmp policy 30
 authentication pre-share
 encryption 3des
 hash sha
 group 5
 lifetime 25200
!
tunnel-group x.x.x.x type ipsec-l2l
tunnel-group x.x.x.x  ipsec-attributes
 pre-shared-key *
!
nat (Inside) 99 access-list CONDITIONAL_NAT
global (Outside) 99 172.19.1.14

I can see traffic for 10.38.49.109 arriving at the firewall - look at the hit count on the ACL, but thats as far as it goes. If I traceroute the 10.38.49.109 address the traffic goes via the outside interface of the firewall, but icmp is blocked at the far end and cannot be enabled.. The 1st phase show cry is sa tells me that phase is not completing and I am assured the far end configuration for the tunnel matches with my end. I did manage to establish conenctivity by hard coding a PC with 172.19.1.14 and could conenct, te tunnel came up etc However i am at a loss as to how to get this to work in the way I need it to.

Could be the configuration i am trying does not work, but it is based on an example from this site, which does give me some confidence.

Any help and advice appreciated. Thanks
0
Comment
Question by:Yorkshire-Matt
2 Comments
 
LVL 79

Accepted Solution

by:
lrmoore earned 500 total points
ID: 24332364
ACL 106 needs to be IP
no access-list 106 line 1 extended permit tcp host 172.19.1.14 10.38.49.0 255.255.255.128
no access-list 106 line 2 extended permit udp host 172.19.1.14 10.38.49.0 255.255.255.128
access-list 106 line 1 extended permit ip host 172.19.1.14 10.38.49.0 255.255.255.128

If phase 1 is not completing, verify the PFS/group settings with the remote end
group 5 is unusual for 3DES/SHA
0
 

Author Closing Comment

by:Yorkshire-Matt
ID: 31579098
he access list and pfs settings were fine, the problem was the remote end had the wrong pre shared key
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
anyconnect password change 2 37
clear arp 1 30
Internet Protocol Security question 3 72
Need help on Windows Firewall blocking program 7 30
I recently attended Cisco Live! in Las Vegas, a conference that boasted over 28,000 techies in attendance, and a week of hands-on learning hosted by a solid partner with which Concerto goes to market.  Every year, Cisco displays cutting-edge technol…
This past year has been one of great growth and performance for OnPage. We have added many features and integrations to the product, making 2016 an awesome year. We see these steps forward as the basis for future growth.
Both in life and business – not all partnerships are created equal. As the demand for cloud services increases, so do the number of self-proclaimed cloud partners. Asking the right questions up front in the partnership, will enable both parties …
Both in life and business – not all partnerships are created equal. Spend 30 short minutes with us to learn:   • Key questions to ask when considering a partnership to accelerate your business into the cloud • Pitfalls and mistakes other partners…

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question