How can I address this issue? Once I need to have my GRE tunnel and interface BE (
inside NAT traffic enters) on the same routing table. Can't I use the global table as my NAT IN?
The inside interface must be in a VRF but the outside interface can be in the global routing table.
This is what you have so far (for NAT):
bundle-ether 2 (NAT_IN) -- ISM -- bundle-ether 21 (NAT_OUT).
Now, if you want to send the NAT'ed traffic over a GRE tunnel, you need to do the following:
bundle-ether 2 (NAT_IN) -- ISM -- bundle-ether 21 (NAT_OUT) -- loopback cable(s) -- bundle-ether 22 (BLUE) -- Tunnel-IP 101 (BLUE)
This is because as I mentioned earlier, ISM traffic cannot be sent to / come from GRE tunnel directly.
Let me know if that works.
Thank you for your attention again. Yes, that's the exactly the configurations I have, but the problem is, once
GRE tunnel currently only supports src/dst resolution in the global routing table and my
src/dst will be in routing table NAT_IN VRF, will I have to use MP-BGP to redistribute my
tunnel's src/dst from VRF NAT_IN to the global table?
Thanks in advance,
One way to solve this restriction would be to have two interfaces (physical or logical) connected to the network. One would be in teh VRF and the other in the global.
You hit the nail right on the head, that's the same solution we found. Now I'm gathering some thoubleshootong commands to check if it's working and test it on a production enviroment.
Thank you Harold and Somnath !!!
Is there a command that shows me the inside address, like show ip nat translations on regular IOS? Could you provide me some troubleshooting commands for CGN on ISM?
Thank you !
You can use the following command:
show cgn nat44 nat1 outside-translation protocol udp outside-address <
port start <
Other commands useful would be:
show cgn nat44 inside-translation ...
show cgn nat44 pool-utilization ...
show cgn nat44 statistics ...
CCO documentation for all commands are available at - http://www.cisco.com/en/US/docs/routers/asr9000/software/asr9k_r4.3/cg_nat/command/reference/b_cgnat_cr42crs_chapter_01.html.
Please use the commands related to NAT44 as that is what you're using.
Hope you are doing well ! Is there any MIB that I can use to monitor the NAT sessions and statistics?
Thanks in advance,
We do not support any CGN MIB yet.
You can possibly use some scripts to capture CLI output periodically.
Thank you Somnath,
I have one more question, What is the impact of changing the [map outside-vrf NAT_OUT address-pool]? I'm asking that because I realized the router is using the network and also the broadcast address of the network I configured as my NAT pool as a valid IP address for translations, I guess I have to avoid it !
Sorry, I could not get your question properly.
If you want to change the address pool while NAT traffic is going on, during the time you're changing the address, traffic will be dropped by CGv6 Application (with "No CGN Config" kind of message).
Once you configure new address pool, you may need to change your static route entry to divert O2I traffic properly.
It is ok to include .0 / .255 in the public IP pool (if that it what you're referring) - there should not be any issue.
Thank you again ! Actually I wondering if using .0 / .255 could be an issue thats why I asked of changing the address pool would be a problem. I'm glad there is no problem using the network and broadcast address.
PS: I'd like to thank you for all your help, now we have GCN with ISM working on a production environment.
That is a great news ! Congratulations !!
Glad to help you out !
It would be great if you can post the final configuration that you're using for your deployment here along with some of the "show" command output (like, 'show cgn ...', 'show interfaces service* [accounting]', etc.).