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Community Member

ISM with NAT44 - Need help with configuration

Hello everyone,

I'm trying to set up NAT44 in the following scenario below and I'm having a hard time figuring out how to redirect the traffic. As you can see the big problem is that I have one single interface that connects to the internal network (10.0.0.0/8) and also to the tunnel destinations all in the same VRF. Can you guys give me a hand? The trafiic comes from network network 10.0.0.0/8 enters interface bundle-ether 2 (Now it needs to be translated), once it is translated, now it needs to reach the destination known via GRE tunnel.

CGN Topology.png

Configurations

-----------------------------------------------

!

vrf NAT_IN

address-family ipv4 unicast

!

!

vrf BLUE

address-family ipv4 unicast

!

!

hw-module service cgn location 0/3/CPU0

!

interface Bundle-Ether2

description UPLINK TO METRO ETHERNET

!

interface Bundle-Ether2.2 l2transport

encapsulation dot1q 2

rewrite ingress tag pop 1 symmetric

!

interface GigabitEthernet200/0/0/43

description LINK TO METRO ETHERNET

bundle id 2 mode active

interface GigabitEthernet300/0/0/43

description LINK TO METRO ETHERNET

bundle id 2 mode active

interface BVI2

description METRO

vrf BLUE

ipv4 address 100.0.0.10/24

!

interface tunnel-ip 101

description GRE_TUNNEL

vrf BLUE

ipv4 address 1.1.1.1/32

tunnel mode gre ipv4

tunnel source interface bvi 2

tunnel destination 200.0.0.1

!

!

interface BVI 100

vrf BLUE

ipv4 address [GATEWAY_100] [MASK_100]

!

interface BVI 200

vrf BLUE

ipv4 address [GATEWAY_200] [MASK_200]

!

interface BVI 300

vrf BLUE

ipv4 address [GATEWAY_300] [MASK_300]

!

!

interface ServiceApp1

vrf NAT_IN

ipv4 address 10.0.2.1 255.255.255.252

service cgn CGN service-type nat44

!

interface ServiceApp2

vrf BLUE

ipv4 address 10.0.2.2 255.255.255.252

service cgn CGN service-type nat44

!

interface ServiceInfra1

ipv4 address 10.0.3.1 255.255.255.0

service-location 0/3/CPU0

!

!

router static

address-family ipv4 unicast

!

vrf NAT_IN

address-family ipv4 unicast

0.0.0.0/0 ServiceApp1

10.0.0.0/8 vrf BLUE bvI 2 <NEXT HOP>

!

!

vrf BLUE

address-family ipv4 unicast

172.16.0.0/24 ServiceApp2

!

!

router ospf METRO

vrf BLUE

router-id [ROUTER_ID]

redistribute bgp 65500 metric 100

area 0

interface bvi 2

!

router ospf BLUE

vrf BLUE

router-id [ROUTER ID]

redistribute bgp 65500 metric 100

area 10

interface BVI100

!

interface BVI200

!

interface BVI200

!

!

!

router bgp 65500

address-family ipv4 unicast

!

address-family vpnv4 unicast

!

!

vrf BLUE

rd 65500:2

address-family ipv4 unicast

redistribute static

redistribute ospf BLUE

!

neighbor 1.1.1.2

remote-as 64512

ebgp-multihop 5

address-family ipv4 unicast

route-policy PASS in

route-policy PASS out

!

!

!

service cgn CGN

service-location preferred-active 0/3/CPU0

service-type nat44 nat44

portlimit 20000

inside-vrf NAT_IN

map outside-vrf BLUE address-pool 172.16.0.0/24

!

!

!

Thanks in advance,

Renato

Everyone's tags (3)
4 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

The following error msg is coming for the same.

tunl_gre_ea[329]: %PLATFORM-TUNL_GRE_EA_PD-4-UNSUPPORTED_CONFIG : GRE Tunnel not supported on this linecard. Set the network topology to avoid this line card for GRE Tunnel packets

Yes, ISM supports traffic from/to bundle interface (along with physical i/f).

Now, as per your configuration, I see:

  • bundle-ether 2 is in NAT_IN VRF and will be receiving inside traffic for NAT. It contains following members:
    • GigabitEthernet200/0/0/43
    • GigabitEthernet300/0/0/43
  • bundle-ether 21 is in NAT_OUT and will be receiving outside traffic for NAT. It contains following members:
    • TenGigE0/0/0/21
    • TenGigE0/0/0/22
  • ServiceInfra configuration:

interface ServiceInfra1

service-location 0/2/CPU0 -> should be 0/3/cpu0 (if you have ISM is slot 3)

  • From NAT perspective, the configuration looks fine.
  • bundle-ether 22 is in BLUE containing the following members. As you said, these are connected via loopback
    • TenGigE0/1/0/21
    • TenGigE0/1/0/22

BTW, which version of XR s/w are you using ? Have you installed the Linux install-kit s/w ?

If it is 4.3.x, you can also refer CGv6 Configuration guide, a CCO document, http://www.cisco.com/en/US/docs/routers/asr9000/software/asr9k_r4.3/cg_nat/configuration/guide/cgnat_43.html for installation and configuration steps.

regards,

Somnath.

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

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.

regards,

Somnath.

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

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.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

That's good to hear !  So, you're all set then, I would assume.

regards,

Somnath.

50 REPLIES
Cisco Employee

ISM with NAT44 - Need help with configuration

Hi Renato,

As I understood from your dscription, traffic for NAT enters the box via bundle-ether 2 interface and after NAT should go out via GRE tunnel (interface tunnel-ip 101).

First of all, there are 2 limitations that you should be aware of:

  • we don't support (on ISM) NAT traffic to come or go via GRE tunnel i/f (to / from ISM). Hence, one work-around could be to send it via any physical interface and use an external loopback cable and then ultimately send it via GRE tunnel i/f.
  • we don't support (on ISM) NAT traffic to come or go via BVI i/f (to / from ISM) as well (not sure, if you're planning to use it for NAT traffic or not).

Once the above 2 are sorted out, NAT configuration would be simple (which you have it almost right). Only thing, you need to have some interface in NAT_IN VRF through which inside NAT traffic enters ASR9K and some interface in BLUE VRF through which outside NAT traffic enters ASR9K.

Let me know if you have more questions.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath Roy,
First of all, thank you for your comments !
Now things are starting to get more clear to me and I guess due to this limitations you just mentioned I'm getting this log messages below, am I right?

: tunl_gre_ea[329]: %PLATFORM-TUNL_GRE_EA_PD-4-UNSUPPORTED_CONFIG : GRE Tunnel not supported on this linecard. Set the network topology to avoid this line card for GRE Tunnel packets

Can I use a L3 bundle-ether interface in place of a BVI, just in case I need to bundle some interfaces. Does ISM support it or I do have to use a physical interface?

I did another config using using loopback cable (Bundle-Ether21 e Bundle-Ether22), could you check this out?

vrf BLUE

address-family ipv4 unicast

!

vrf NAT_OUT

address-family ipv4 unicast

!

vrf NAT_IN

address-family ipv4 unicast

!

hw-module service cgn location 0/3/CPU0

!

interface Bundle-Ether2

vrf NAT_IN

description UPLINK TO METRO ETHERNET

ipv4 address 100.0.0.10/24

!

interface GigabitEthernet200/0/0/43

description LINK TO METRO ETHERNET

bundle id 2 mode active

!

interface GigabitEthernet300/0/0/43

description LINK TO METRO ETHERNET

bundle id 2 mode active

!

interface Bundle-Ether21

vrf NAT_OUT

ipv4 address 10.0.1.1 255.255.255.0

!

interface Bundle-Ether22

vrf BLUE

ipv4 address 10.0.1.2 255.255.255.0

!

interface TenGigE0/0/0/21

bundle id 21 mode on

!

interface TenGigE0/0/0/22

bundle id 21 mode on

!

interface TenGigE0/1/0/21

bundle id 22 mode on

!

interface TenGigE0/1/0/22

bundle id 22 mode on

!

!

interface tunnel-ip 101

description GRE_TUNNEL

vrf BLUE

ipv4 address 1.1.1.1/32

tunnel mode gre ipv4

tunnel source interface bundle-ether 2

tunnel destination 200.0.0.1

!

!

interface BVI 100

vrf BLUE

ipv4 address [GATEWAY_100] [MASK_100]

!

interface BVI 200

vrf BLUE

ipv4 address [GATEWAY_200] [MASK_200]

!

interface BVI 300

vrf BLUE

ipv4 address [GATEWAY_300] [MASK_300]

!

!

interface ServiceApp1

vrf NAT_IN

ipv4 address 10.0.2.1 255.255.255.0

service cgn CGN service-type nat44

!

interface ServiceApp2

vrf NAT_OUT

ipv4 address 10.0.2.2 255.255.255.0

service cgn CGN service-type nat44

!

interface ServiceInfra1

ipv4 address 10.0.3.1 255.255.255.0

service-location 0/2/CPU0

!

router static

address-family ipv4 unicast

!

vrf NAT_IN

address-family ipv4 unicast

0.0.0.0/0 ServiceApp1

!

!

vrf NAT_OUT

address-family ipv4 unicast

0.0.0.0/0 10.0.1.2

172.16.0.0/24 ServiceApp2

!

!

vrf BLUE

address-family ipv4 unicast

172.16.0.0/24 10.0.1.1

!

!

router ospf METRO

vrf NAT_IN

router-id [ROUTER_ID]

redistribute bgp 65500 metric 100

area 0

interface bundle-ether 2

!

router ospf BLUE

vrf BLUE

router-id [ROUTER ID]

redistribute bgp 65500 metric 100

area 10

interface BVI100

!

interface BVI200

!

interface BVI200

!

!

!

router bgp 65500

address-family ipv4 unicast

!

address-family vpnv4 unicast

!

!

vrf BLUE

rd 65500:2

address-family ipv4 unicast

redistribute static

redistribute ospf BLUE

!

neighbor 1.1.1.2

remote-as 64512

ebgp-multihop 5

address-family ipv4 unicast

route-policy PASS in

route-policy PASS out

!

vrf NAT_IN

rd 65500:3

address-family ipv4 unicast

!

service cgn CGN

service-location preferred-active 0/3/CPU0

service-type nat44 nat44

portlimit 20000

inside-vrf NAT_IN

map outside-vrf NAT_OUT address-pool 172.16.0.0/24

Thanks !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

The following error msg is coming for the same.

tunl_gre_ea[329]: %PLATFORM-TUNL_GRE_EA_PD-4-UNSUPPORTED_CONFIG : GRE Tunnel not supported on this linecard. Set the network topology to avoid this line card for GRE Tunnel packets

Yes, ISM supports traffic from/to bundle interface (along with physical i/f).

Now, as per your configuration, I see:

  • bundle-ether 2 is in NAT_IN VRF and will be receiving inside traffic for NAT. It contains following members:
    • GigabitEthernet200/0/0/43
    • GigabitEthernet300/0/0/43
  • bundle-ether 21 is in NAT_OUT and will be receiving outside traffic for NAT. It contains following members:
    • TenGigE0/0/0/21
    • TenGigE0/0/0/22
  • ServiceInfra configuration:

interface ServiceInfra1

service-location 0/2/CPU0 -> should be 0/3/cpu0 (if you have ISM is slot 3)

  • From NAT perspective, the configuration looks fine.
  • bundle-ether 22 is in BLUE containing the following members. As you said, these are connected via loopback
    • TenGigE0/1/0/21
    • TenGigE0/1/0/22

BTW, which version of XR s/w are you using ? Have you installed the Linux install-kit s/w ?

If it is 4.3.x, you can also refer CGv6 Configuration guide, a CCO document, http://www.cisco.com/en/US/docs/routers/asr9000/software/asr9k_r4.3/cg_nat/configuration/guide/cgnat_43.html for installation and configuration steps.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

Thank you ! I'm using version 4.3.1. I didn`t know I have to install it (haha), is it mandatory?

Thank you again !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

Yes, installing the Linux install-kit is mandatory as the crux of CGv6 application is part of it.

Please follow the instruction for installing Linux install-kit for 4.2in the CCO document I sent (specifically - http://www.cisco.com/en/US/docs/routers/asr9000/software/asr9k_r4.3/cg_nat/configuration/guide/cgnat43cgn.html#wp1015556). Method for 4.2.1 and above releases is the same.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

Is it necessary even when I'm using only NAT44? Do you know where I can find the information about the limitations of ISM you mentioned?

Thank you !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Reneto,

Yes, CGv6/CGN functionality is provided by same install-kit. So, you must install the same.

At present, CCO documents are the only external documentation. But, I do see that it does not list some of these limitations. We need to add it to the document.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

Thank you so much for your attention. I've installed the linux kit and now the module is in

APP-READY state.

Thank you very much again !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

You are welcome :-)

That's great ! Now, you can try with some NAT traffic.

Community Member

Re: ISM with NAT44 - Need help with configuration

Yeah, I'm going to test it as soon as possible. I'm also having some issue setting up a GRE tunnel on ASR9K, can you help with that or should I open another discussion?

Thanks

Renato Reis

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

For GRE tunnel, it would be better to open a separate discussion. You can also check available CCO documentation first to see if you can get answer there. (Reference: http://www.cisco.com/en/US/products/ps9853/products_installation_and_configuration_guides_list.html).

regards,

Somnath.

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

Could you pelase let us know what kind of issue you have in setting up the GRE tunnel?

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Harold,

I've configured a GRE tunnel between 2 ASR9K6 and I'm having the following issues:

1) The tunnel interface is UP but I can't ping the tunnels IP addresses, not even my own tunnel's interface IP address so that I never know if the tunnel is working properly.

2) I don't see the (tunnel vrf [VRF]) on IOS-XR, to tell that my tunnel interface is in VRF BLUE, but my tunnel destination is in VRF NAT_IN.

Configurations

----------------------------------------

ASR01

------------

interface tunnel-ip101

description TUNNEL_1

vrf BLUE

ipv4 address 1.1.1.2 255.255.255.252

tunnel mode gre ipv4

tunnel source Bundle-Ether2

keepalive 10 3

tunnel destination [TUNNEL IP DESTINATION]

!

ASR02

------------

interface tunnel-ip101

description TUNNEL_1

vrf BLUE

ipv4 address 1.1.1.1 255.255.255.252

tunnel mode gre ipv4

tunnel source BVI2

keepalive 10 3

tunnel destination [TUNNEL IP DESTINATION]

Thank you !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

The VRF aware GRE tunnel currently only supports src/dst resolution in the global routing table. Support for src/dst resolution in a VRF is planned for 5.2.0.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath/Harold,

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?

Thanks

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

The inside interface must be in a VRF but the outside interface can be in the global routing table.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

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.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

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,

Renato Reis

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

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.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Harold,

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 !!!

Regards,

Renato

Community Member

Re: ISM with NAT44 - Need help with configuration

HiSomnath Roy,

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 !

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

You can use the following command:

show cgn nat44 nat1 outside-translation protocol udp outside-address <100.200.2.75> port start <1> end <65535>

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.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Thank you Somnath !

[]'s

Renato Reis

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

Hope you are doing well ! Is there any MIB that I can use to monitor the NAT sessions and statistics?

Thanks in advance,

Renato Reis

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

We do not support any CGN MIB yet.

You can possibly use some scripts to capture CLI output periodically.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

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 !

Thank you,

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

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.

regards,

Somnath.

Community Member

Re: ISM with NAT44 - Need help with configuration

Hi Somnath,

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.

Thanks,

Renato

Cisco Employee

Re: ISM with NAT44 - Need help with configuration

Hi Renato,

           

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.).

regards,

Somnath.

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