03-04-2014 02:27 PM - edited 03-04-2019 10:29 PM
Hello all,
We have a Site-to-Site VPN that is securing all traffic to/from 10.160.8.0/24 to/from 10.0.0.0/8. This is for everything - including Internet traffic. However, there is an exception (of course)...
The part I cannot get working is if traffic comes from the VPN (10.0.0.0/8) to 10.160.8.5 (on 80 or 443) then the return traffic must go back over the VPN. BUT, if the 80 or 443 traffic comes from anyplace else (Internet via X.X.X.X that gets translated to 10.160.8.5), then it needs to be NATed back out to the Internet via Gig2.
I have the following configuration (tried to just have the neccessarry lines)...
interface GigabitEthernet2
ip address Y.Y.Y.Y 255.255.255.0 !! the X.X.X.X and Y.Y.Y.Y are in the same subnet
ip address X.X.X.X 255.255.255.0 secondary
ip nat outside
crypto map ipsec-map-S2S
interface GigabitEthernet4.2020
description 2020
encapsulation dot1Q 2020
ip address 10.160.8.1 255.255.255.0
ip nat inside
ip virtual-reassembly
ip nat inside source list NAT-Outbound interface GigabitEthernet2 overload
ip nat inside source static tcp 10.160.8.5 80 X.X.X.X 80 route-map NO-NAT extendable
ip nat inside source static tcp 10.160.8.5 443 X.X.X.X 443 route-map NO-NAT extendable
ip access-list extended NAT-Outbound
deny tcp host 10.160.8.5 10.0.0.0 0.0.0.255 eq www
deny tcp host 10.160.8.5 10.0.0.0 0.0.0.255 eq 443
permit tcp host 10.160.8.5 any eq www
permit tcp host 10.160.8.5 any eq 443
ip access-list extended NO-NAT
deny tcp host 10.160.8.5 10.0.0.0 0.0.0.255 eq www
deny tcp host 10.160.8.5 10.0.0.0 0.0.0.255 eq 443
permit ip any any
route-map NO-NAT permit 10
match ip address NO-NAT
With the above configuration, we can get to 10.160.8.5 from the Internet but cannot get to it over over the VPN tunnel (from 10.200.0.0/16). If I remove the two "ip nat inside source static..." commands, then the opposite happens - I can then get to 10.160.8.5 from he VPN tunnel but I now cannot get to it from the Internet.
How can I get to it from both? It seems that when I hit the first NAT statement (Gig2 overload) that the "deny" in the NAT-Outbound ACL punts me out of that NAT statement. It then processes the next NAT statement (one of the "ip nat inside source static...") but the "deny" in the NO-NAT ACL does not seem to punt me out of that NAT statement. That is my theory anyway (maybe something else is going on?)
Should this work like this or am I not understanding something correctly? This is on a Cisco Cloud Services Router (CSR 1000v).
Thanks!
Solved! Go to Solution.
03-05-2014 08:18 AM
Your netmask is wrong for your 10.0.0.0/8. I would not worry about port/protocol either since that can screw you up. A better way to do it would be to deny all IP vpn traffic.
ip access-list extended NAT-Outbound
deny ip 10.160.8.0 0.0.0.0.255 10.0.0.0 0.255.255.255
...
ip access-list extended NO-NAT
deny ip 10.160.8.0 0.0.0.0.255 10.0.0.0 0.255.255.255
permit ip any any
Doc:
Configuring IPSec Router-to-Router with NAT Overload and Cisco Secure VPN Client
Thanks,
Brendan
03-05-2014 08:18 AM
Your netmask is wrong for your 10.0.0.0/8. I would not worry about port/protocol either since that can screw you up. A better way to do it would be to deny all IP vpn traffic.
ip access-list extended NAT-Outbound
deny ip 10.160.8.0 0.0.0.0.255 10.0.0.0 0.255.255.255
...
ip access-list extended NO-NAT
deny ip 10.160.8.0 0.0.0.0.255 10.0.0.0 0.255.255.255
permit ip any any
Doc:
Configuring IPSec Router-to-Router with NAT Overload and Cisco Secure VPN Client
Thanks,
Brendan
03-05-2014 01:36 PM
Thanks Brendan!
Fixing the netmask was good (doh!! oh my part) but changing the NO-NAT ACL from deny tcp (with a port) to a deny ip did the trick.
Thanks!
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