| Exam 400-101 | Question id=935 | VPN Technologies |
You issue the show ip nhrp detail command on RouterA and receive the following output:
RouterA# show ip nhrp detail
10.1.1.2/32 via 10.1.1.2, Tunnel1 created created 22:59:16, never expire
Type: static, Flags: used
NBMA address: 192.168.51.50
10.1.1.3/32 via 10.1.1.3, Tunnel1 created 21:59:16, expire 01:20:44
Type: dynamic, Flags: authoritative unique nat registered used
NBMA address: 172.16.0.44
Which of the following flags indicates that the entry cannot be overwritten by a different NBMA entry with the same IP address?
| A. |
authoritative | |
| B. |
nat | |
| C. |
registered | |
| D. |
unique | |
| E. |
used |
Of the available choices, the unique flag in the output of the show ip nhrp detailcommand indicates that the entry cannot be overwritten by another nonbroadcast multiaccess (NBMA) entry with the same IP address. Similar to Address Resolution Protocol (ARP) on broadcast networks, Next Hop Resolution Protocol (NHRP) enables devices on an NBMA network to dynamically discover the physical addresses of other devices on the network. The show ip nhrp command displays information about NHRP mappings. When issued with the detail keyword, this command displays more detailed information about those mappings, including a list of flags.
The show ip nhrp detail command might display any of the following flags for a given entry:
- authoritative -The mapping was obtained directly from the nexthop router or server.
- implicit -The mapping was obtained from an NHRP resolution request or packet.
- local -The mapping isfor networks that are local to the router.
- nat -The remote device supports NHRP Network Address Translation (NAT) extensions.
- negative -A mapping could not be obtained for negative caching.
- (no socket) -IP Security (IPSec) will not set up encryption, because data traffic does not require thistunnel.
- registered-The mapping was created in response to an NHRP registration.
- router -The mappings for aremote router are marked with the router flag.
- unique -The mapping cannot be overwritten by a different NBMA entry with the same IP address.
- used-Data packets are being process switched for the given mapping.