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Proxy arp not working on the nat outside interface (participating in a VRF)

 

My Router is not making the acting as a Proxy for the ARP requests for the NATted IP's on the NAT oustide intterface. Here's the interface config :

 

ISR#sh run int fa0/0.101
Building configuration...

Current configuration : 169 bytes
!
interface FastEthernet0/0.101
 encapsulation dot1Q 101
 ip vrf forwarding Hydrol
 ip address 192.168.101.254 255.255.255.0
 ip nat outside
 ip virtual-reassembly
end

 

Interface FastEthernet0/0 is connected to another router which is the gateway for Vlan101 and has the IP: 192.168.101.1

ISR#sh run int vlan444
Building configuration...

Current configuration : 156 bytes
!
interface Vlan444
 ip vrf receive Hydrol
 ip address 11.0.0.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 ip policy route-map VRF_TO_GLOBAL
end

Router is doing following NAT:

ip nat inside source static 11.0.0.3 192.168.101.36

Routing is setup fine, and 11.0.0.3 should be able to ping 192.168.101.1. ICMP Packet reaches till the gateway - but when the gateway tries to ARP for 192.168.101.36 , the NAT router does not respond to the ARP request. I've tried manually entering ip-proxy arp on the interface, but it has not effect because it is a default command.

When i manually enter a static ARP entry for 192.168.101.36 on the gateway device - pointing to the NAT outside interface MAC address- everything works as expected.

I've tried multiple router series (3945,4500,IR) to do the NAT function with the similar config/setup - and i saw this issue on all series So i'm sure it's a config issue - not the device issue.

Is there something more to be done when the NAT outside interface is in a VRF - to make the proxy-arp work

Please help !

2 Replies 2

JimWicks
Level 1
Level 1

try tagging your NAT statement with the VRF, something like the following

 

ip nat inside source static 11.0.0.3 192.168.101.36 vrf Hydrol

Hello
Try using NVI nat (domianless nat) and also check your vrf table for default route 

sh ip route vrf Hydrol

Int fa0/0.1.01
no ip nat outside
ip nat enable

int vlan 44
no ip nat inside
ip nat enable

ip nat source static 11.0.0.3 192.168.101.36
ip route vrf Hydrol 0.0.0.0 0.0.0.0 fa0/0.101 192.168.101.x


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Kind Regards
Paul
Review Cisco Networking products for a $25 gift card