By issuing the command ip nat inside on a fastethernet interface i got this result:
*Mar 1 01:09:14.867: %LINEPROTO-5-UPDOWN: Line protocol on Interface NVI0, changed state to up
NVI0 is up, line protocol is up
Hardware is NVI
Interface is unnumbered. Using address of FastEthernet0/0 (18.104.22.168)
MTU 1514 bytes, BW 10000000 Kbit, DLY 0 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation UNKNOWN, loopback not set
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
Just curious, what does this NVIO interface do? It's not really mentioned on the NAT theory. The links i've read so far are a bit vague on the subject.
Maybe someone can elaborate more?
IOS on the router C3725-ADVENTERPRISEK9-M
This is the NAT Virtual Interface on ISR routers.
One of the cool things, by virtue of having one of these around, is that you no longer need to worry about your "inside" or "outside" locations... If you have a lot of complex NAT this is very handy.
Now you just need "ip nat enable" and the NVI will take care of the rest.
A. Cisco recommends that you use legacy NAT for VRF to global NAT (ip nat inside/out) and between interfaces in the same VRF. NVI is used for NAT between different VRFs.
I am trying to find out if NVI is now the recommended way for doing NAT configuration in all cases.
Very cool feature, just found a link on cisco's site with more config examples.
Going to try it out.