09-10-2008 03:02 AM - edited 03-09-2019 09:26 PM
Hello there,
i hope someone knows this better than me:
I have sometimes the "wrong" address on the NVI0 Interface. i use the "old" nat configuration with nat inside and nat outside. sometimes the address of the nvi is the one from a local loopback (then everything works, like ospf between two routers) and the next router has the outside interface address on the nvi. how is this decision made?
----------------------------------------
NVI0 is up, line protocol is up
Interface is unnumbered. Using address of Loopback10 (10.51.2.10)
Broadcast address is 255.255.255.255
MTU is 1514 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Multicast reserved groups joined: 224.0.0.5
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is disabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is disabled
IP Null turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is disabled
Network address translation is disabled
BGP Policy Mapping is disabled
WCCP Redirect outbound is disabled
WCCP Redirect inbound is disabled
WCCP Redirect exclude is disabled
----------------------------------------
NVI0 is up, line protocol is up
Interface is unnumbered. Using address of FastEthernet0/0 (87.193.***.***)
Broadcast address is 255.255.255.255
MTU is 1514 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is disabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is disabled
IP Null turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is disabled
Network address translation is disabled
BGP Policy Mapping is disabled
WCCP Redirect outbound is disabled
WCCP Redirect inbound is disabled
WCCP Redirect exclude is disabled
--------------------------------------
thanks in advance
Solved! Go to Solution.
09-11-2008 05:38 AM
NVI is a new feature in IOS 12.3 and later.
It is enabled by using "ip nat enable " on interfaces and we do not use "ip nat inside" or "ip nat outside" .
If you want to understand how translation and routing differs in the implementation check following link :
http://blog.internetworkexpert.com/2008/02/15/the-inside-and-outside-of-nat/
09-10-2008 06:48 AM
Hello,
NVI is enabled and it takes ip address from the interface under which you configure "ip nat enable"
in your first example if you check you should see "ip nat enable" under interface loopback10 and for second example under interface FastEthernet0/0 .
Also check follwoing link:
http://www.cisco.com/en/US/docs/ios/12_4t/ip_addr/configuration/guide/htaddrs.html#wp1084652
HTH
Saju
Pls rate if it helps
09-10-2008 10:50 PM
I found this document before, but i did not use the "ip nat enable".
It is a 12.4-15T7 image.
I have used the ip nat outside and inside command.
can you explain me how this interface nvi is used? i did not get it i think.
09-11-2008 05:38 AM
NVI is a new feature in IOS 12.3 and later.
It is enabled by using "ip nat enable " on interfaces and we do not use "ip nat inside" or "ip nat outside" .
If you want to understand how translation and routing differs in the implementation check following link :
http://blog.internetworkexpert.com/2008/02/15/the-inside-and-outside-of-nat/
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