As I asked here and duplicated here it appears NAT Hairpinning is the answer I'm looking for to allow internal servers to loopback through the ASA to access external IP's (without using DNS Doctoring). However, the instructions presented in those posts, and here, http://www.cisco.com/en/US/products/ps6120/products_configuration_example09186a00807968d1.shtml#solution2 do not seem to cover NAT Hairpinning on IOS 8.3+ (I'm running 9.1) 9.1 doesn't even have the static command (by itself) anymore.
How do I NAT Hairpin in IOS 8.3+ (specifically 9.1(2) on a Cisco ASA 5505).
This is what I posted to Cisco's Support site... perhaps the additional information makes my situation more clear
I can't seem to get nat hairpinning to work... Most instructions on the internet indicate how to do this with commands available prior to 8.3.
I've tried the following:
same-security-traffic permit intra-interface asa-box(config-network-object)# object network my-inside-address-obj asa-box(config-network-object)# nat (inside,inside) static my-outside-address-obj
which didn't work.
Then I added:
access-list hairpin_allow extended permit tcp object Internal_NAT_Range object External_NAT_Range
access-group hairpin_allow in interface inside
which also didn't work (trying to show due dilligence here...).
Then I tried:
nat (inside,inside) source static Internal_NAT_Range Internal_NAT_Range destination static External_NAT_Range External_NAT_Range
Still a no go.
Finally, I performed these steps (as seen here): "9. To avoid packet-drops due to the asymmetric nature of routing that's occuring internally, we need the ASA to bypass stateful inspection for this particular traffic. For this, we need to configure the following:
ASA(config)#access-list tcp_bypass extended permit tcp object Internal_NAT_Range object External_NAT_Range !--- Configure the access list to specify the TCP traffic !--- that needs to by-pass inspection to improve the performance.
!--- Configure the class map and specify the match parameter for the !--- class map to match the interesting traffic.
ASA(config)#class-map tcp_bypass ASA(config-cmap)#description "TCP traffic that bypasses stateful firewall" ASA(config-cmap)#match access-list tcp_bypass
!--- Configure the policy map and specify the class map !--- inside this policy map for the class map.
ASA(config-cmap)#policy-map tcp_bypass_policy ASA(config-pmap)#class tcp_bypass
!--- Use the set connection advanced-options tcp-state-bypass !--- command in order to enable TCP state bypass feature.
ASA(config-pmap-c)#set connection advanced-options tcp-state-bypass
!--- Use the service-policy policymap_name [ global | interface intf ] !--- command in global configuration mode in order to activate a policy map !--- globally on all interfaces or on a targeted interface.
ASA(config-pmap-c)#service-policy tcp_bypass_policy inside"
My config (clean/before any of the above) is as follows...
... object network External_NAT_Range range x.x.56.3 x.x.59.255 object network Internal_NAT_Range range 172.17.56.3 172.17.59.255 object network InternalIPs subnet 172.17.56.0 255.255.248.0 object network VpnIPs subnet 172.17.63.0 255.255.255.0 object network InternalIPs_OutOnly range 172.17.60.1 172.17.62.254 ... nat (inside,outside) source static InternalIPs InternalIPs destination static VpnIPs VpnIPs no-proxy-arp route-lookup description Un-Nats VPN IPs nat (inside,outside) source dynamic InternalIPs_OutOnly interface description Allows remaining interior network to access the Internet ! object network Internal_NAT_Range nat (inside,outside) static External_NAT_Range net-to-net access-group outside_access_in in interface outside route outside 0.0.0.0 0.0.0.0 x.x.56.1 1 ...
I just want to be able to access an external resource, say, http://x.x.56.5 from an internal IP, say, 172.17.56.8
I tried to use DNS doctoring. The configuration was much simpler, and worked, but when PTR requests came in from the internet, DNS Doctoring seemed to also translate the outbound responses to reflect my internal IP's which was obviously quite wrong...
Any help from you Cisco pros would be appreciated!