Hi Pros,
Got a network with 2 WAN Routers and a LAN.
Users across LAN need to access a server in my LAN with IP Address 10.30.247.101.
The users in WAN already have the subnet in their local LAN (overlapping) and thats the reason NAT is implemented.
Now, one of my colleagues had configured NAT as below:
ip nat inside source static 10.30.247.101 10.192.1.212
That means WAN users access server by giving IP 10.192.1.212 and it gets translated into 10.30.247.101.
This config is done on both routers as they are redundant with HSRP.
We are hitting on these logging messages every 30 secs on both routers.
Nov 20 15:33:48.882 IN: %IP-4-DUPADDR: Duplicate address 10.192.1.212 on FastEth
ernet0/1, sourced by 0004.9a39.1fb1
This mac is found to be of second router.
Config of R1 is below:
interface Multilink1
description *** Multilink for 2 X E1 Singtel to Sprtc37-Multilink1 s2/0 and s1/
0 ***
bandwidth 4000
ip address 10.8.16.54 255.255.255.252
ip access-group SQL2000_block in
ip accounting output-packets
ip nat outside
ip route-cache flow
ip summary-address eigrp 7 10.192.128.0 255.255.128.0 5
ip summary-address eigrp 7 10.192.7.0 255.255.255.0 5
ip summary-address eigrp 7 10.192.0.0 255.255.128.0 5
load-interval 30
delay 2000
ppp multilink
multilink-group 1
!
interface FastEthernet0/0
description **** Dealing Room LAN in FBB Connects to SWIN02 Port 2/4 ****
ip address 10.192.7.251 255.255.255.0
ip helper-address 10.192.0.211
ip helper-address 10.192.0.212
no ip redirects
ip route-cache flow
speed 100
full-duplex
standby ip 10.192.7.254
!
interface FastEthernet0/1
description **** Connects to FBB Backbone LAN Connects to SWIN02 Port 2/3 ****
ip address 10.192.1.251 255.255.254.0
ip helper-address 10.192.128.215
ip helper-address 10.192.1.234
ip helper-address 10.192.0.234
no ip redirects
ip nat inside
ip route-cache flow
speed 100
full-duplex
standby ip 10.192.1.254
Config of R2 is below:
interface FastEthernet0/1
description **** Connects to FBB Backbone LAN Connects to SWIN01 Port 2/3 ****
ip address 10.192.1.252 255.255.254.0
ip helper-address 10.192.128.215
ip helper-address 10.192.0.234
ip nat inside
ip policy route-map wp_policy
speed 100
full-duplex
standby ip 10.192.1.254
!
interface Ethernet1/0
description Connectivity to Akruti ( 10 Mbps Actual )
ip address 10.192.250.85 255.255.255.252
ip accounting output-packets
ip nat outside
ip route-cache flow
full-duplex
!
interface Serial1/0
description Connectivity to Akruti (2 MBPS Actual)
ip address 10.192.250.73 255.255.255.252
ip accounting output-packets
ip nat outside
ip route-cache flow
no fair-queue
serial restart-delay 0
Is it because we are translating a IP address coming from interface fa0/1 to IP address in same subnet of interface fa0/1 (10.192.1.252 255.255.254.0) that NAT is throwing up such messages ?
