3 Replies Latest reply: May 4, 2014 10:33 PM by Alexander RSS

    An IP address of USA Department of Defense Network Information Center in debug output of a router




      TAC Engineer has opened the bug CSCuo38544 -  Strange IP in debug when policy routing, but the "Strange IP" is actually the IP address of DoD Network Information Center.


      Here is the output of debug ip packet:

      Mar 20 12:41:13.038: IP: route map rm-pbr-nat-loop, item 100, permit

      Mar 20 12:41:13.038: IP: s= (GigabitEthernet0/0), d= (Loopback0), len 100, policy routed

      Mar 20 12:41:13.038: IP: GigabitEthernet0/0 to Loopback0


      Mar 20 12:41:13.038: IP: s= (GigabitEthernet0/0), d= (Loopback0), len 100, output feature, NAT ALG proxy(59), rtype 2, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

      Mar 20 12:41:13.038: IP: s= (GigabitEthernet0/0), d= (Loopback0), g=, len 100, forward

      Mar 20 12:41:13.038: IP: s= (GigabitEthernet0/0), d= (Loopback0), len 100, sending full packet


      Can anyone explain, why does it popup in debug output?

      Is such ip addresses hardwired in IOS?


      To test this you need configure NAT on a Stick according to my scenario, I have only changed the first and the second octet in the ip addresses:

      IOS 15.3(3)M2


      interface Loopback0

      ip address

      ip nat inside

      ip virtual-reassembly in


      interface GigabitEthernet0/0

      ip address

      no ip proxy-arp

      ip nat outside

      ip virtual-reassembly in

      ip policy route-map rm-pbr-nat-loop


      ip nat inside source list NAT-Loop interface GigabitEthernet0/0 overload

      ip nat outside source static no-alias


      ip route GigabitEthernet0/0


      ip access-list extended NAT-Loop

      permit ip host any


      ip access-list extended PBR-NAT-Loop

      permit ip host host


      route-map rm-pbr-nat-loop permit 100

      match ip address PBR-NAT-Loop

      set interface Loopback0


      access-list 90 permit


      Then debug ip packet 90 and debug ip policy


      And ping from



      Network diagram in the attachment.


      Thank you.