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Contents
- DMVPN Configuration Using FQDN
- Finding Feature Information
- Prerequisites for DMVPN Configuration Using FQDN
- Restrictions for DMVPN Configuration Using FQDN
- Information About DMVPN Configuration Using FQDN
- DNS Functionality
- DNS Server Deployment Scenarios
- How to Configure DMVPN Configuration Using FQDN
- Configuring a DNS Server on a Spoke
- Configuring a DNS Server
- Configuring an FQDN with a Protocol Address
- Configuring a FQDN Without an NHS Protocol Address
- Verifying DMVPN FQDN Configuration
- Configuration Examples for DMVPN Configuration Using FQDN
- Example Configuring a Local DNS Server
- Example Configuring an External DNS Server
- Example Configuring NHS with a Protocol Address and an NBMA Address
- Example Configuring NHS with a Protocol Address and an FQDN
- Example Configuring NHS Without a Protocol Address and with an NBMA Address
- Example Configuring NHS Without a Protocol Address and with an FQDN
- Additional References
- Feature Information for DMVPN Configuration Using FQDN
DMVPN Configuration Using FQDN
The DMVPN Configuration Using FQDN feature enables next hop clients (NHCs) to register with the next hop server (NHS).
This feature allows you to configure a fully qualified domain name (FQDN) for the nonbroadcast multiple access network (NBMA) address of the hub (NHS) on the spokes (NHCs). The spokes resolve the FQDN to IP address using the DNS service and get registered with the hub using the newly resolved address. This allows spokes to dynamically locate the IP address of the hub using FQDN.
With this feature, spokes need not configure the protocol address of the hub. Spokes learn the protocol address of the hub dynamically from the NHRP registration reply of the hub. According to RFC 2332, the hub to which the NHRP registration was sent responds with its own protocol address in the NHRP registration reply and hence the spokes learn the protocol address of the hub from the NHRP registration reply packet.
In Cisco IOS Release 15.1(2)T and earlier releases, in Dynamic Multipoint VPN (DMVPN), NHS NBMA addresses were configured with either IPv4 or IPv6 addresses. Because NHS was configured to receive a dynamic NBMA address, it was difficult for NHCs to get the updated NBMA address and register with the NHS. This limitation is addressed with the DMVPN Configuration Using FQDN feature. This feature allows NHC to use an FQDN instead of an IP address to configure NBMA and register with the NHS dynamically.
- Finding Feature Information
- Prerequisites for DMVPN Configuration Using FQDN
- Restrictions for DMVPN Configuration Using FQDN
- Information About DMVPN Configuration Using FQDN
- How to Configure DMVPN Configuration Using FQDN
- Configuration Examples for DMVPN Configuration Using FQDN
- Additional References
- Feature Information for DMVPN Configuration Using FQDN
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for DMVPN Configuration Using FQDN
Cisco IOS Domain Name System (DNS) client must be available on the spoke.
Restrictions for DMVPN Configuration Using FQDN
If the NBMA IP address resolved from the FQDN is not mapped to an NHS configured with the protocol address, the spoke cannot register with the hub.
Information About DMVPN Configuration Using FQDN
DNS Functionality
A Domain Name System (DNS) client communicates with a DNS server to translate a hostname to an IP address.
The intermediate DNS server or the DNS client on the route enters the FQDN DNS reply from the DNS server into the cache for a lifetime. If the DNS client receives another query before the lifetime expires, the DNS client uses the entry information from the cache. If the cache expires, the DNS client queries the DNS server. If the NBMA address of the NHS changes frequently, the DNS entry lifetime must be short, otherwise the spokes may take some time before they start using the new NBMA address for the NHS.
DNS Server Deployment Scenarios
A DNS server can be located either in a hub network or outside a hub and spoke network.
Following are the four DNS server load balancing models:
- Round robin--Each DNS request is assigned an IP address sequentially from the list of IP addresses configured for an FQDN.
- Weighted round robin--This is similar to round-robin load balancing except that the IP addresses are assigned weights and nodes, where higher weights can take more load or traffic.
- Geography or network--Geography-based load balancing allows the requests to be directed to the optimal node that is geographically the nearest or the most efficient to the requester.
- Failover--Failover load balancing sends all requests to a single host until the load balancer determines a particular node to be no longer available. It then directs traffic to the next node available in the list.
How to Configure DMVPN Configuration Using FQDN
- Configuring a DNS Server on a Spoke
- Configuring a DNS Server
- Configuring an FQDN with a Protocol Address
- Configuring a FQDN Without an NHS Protocol Address
- Verifying DMVPN FQDN Configuration
Configuring a DNS Server on a Spoke
Perform this task to configure a DNS server on a spoke. You must perform this task only if you want to resolve FQDN using an external DNS server.
DETAILED STEPS
Configuring a DNS Server
DETAILED STEPS
Configuring an FQDN with a Protocol Address
Perform this task to configure an FQDN with a protocol address. You must know the protocol address of the NHS while you are configuring the FQDN. This configuration registers spoke to a hub using NBMA.
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode.
| ||
Step 2 |
configure
terminal
Example: Router# configure terminal |
Enters global configuration mode. | ||
Step 3 |
interface
tunnel
number
Example: Router(config)# interface tunnel 1 |
Enters interface configuration mode. | ||
Step 4 |
ip
nhrp
nhs
nhs-address
[nbma {nbma-address | FQDN-string}] [multicast] [priority value] [cluster number] Example: Router(config-if)# ip nhrp nhs 192.0.2.1 nbma examplehub.example1.com multicast |
Registers a spoke to a hub.
| ||
Step 5 |
end
Example: Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
Configuring a FQDN Without an NHS Protocol Address
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode.
| ||
Step 2 |
configure
terminal
Example: Router# configure terminal |
Enters global configuration mode. | ||
Step 3 |
interface
tunnel
number
Example: Router(config)# interface tunnel 1 |
Enters interface configuration mode. | ||
Step 4 |
ip
nhrp
nhs
dynamic
nbma
{nbma-address | FQDN-string} [multicast] [priority value] [cluster value] Example: Router(config-if)# ip nhrp nhs dynamic nbma examplehub.example1.com |
Registers a spoke to a hub.
| ||
Step 5 |
end
Example: Router(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
Verifying DMVPN FQDN Configuration
This task shows how to display information to verify DMVPN FQDN configuration. The following show commands can be entered in any order.
DETAILED STEPS
| Step 1 |
enable
Enables privileged EXEC mode. Enter your password if prompted. Example:
Router# enable
|
| Step 2 |
show
dmvpn
Displays DMVPN-specific session information. Example:
Router# show dmvpn
Legend: Attrb --> S - Static, D - Dynamic, I - Incomplete
N - NATed, L - Local, X - No Socket
# Ent --> Number of NHRP entries with same NBMA peer
NHS Status: E --> Expecting Replies, R --> Responding, W --> Waiting
UpDn Time --> Up or Down Time for a Tunnel
==========================================================================
Interface: Tunnel1, IPv4 NHRP Details
Type:Spoke, NHRP Peers:1,
# Ent Peer NBMA Addr Peer Tunnel Add State UpDn Tm Attrb
----- --------------- --------------- ----- -------- -----
1 192.0.2.1 192.0.2.2 UP 00:00:12 S
(h1.cisco.com)
|
| Step 3 |
show
ip
nhrp
nhs
Displays the status of the NHS. Example:
Router# show ip nhrp nhs
IPv4 Registration Timer: 10 seconds
Legend: E=Expecting replies, R=Responding, W=Waiting
Tunnel1:
192.0.2.1 RE NBMA Address: 192.0.2.2 (h1.cisco.com) priority = 0 cluster = 0
|
| Step 4 |
show
running-config
interface
tunnel
tunnel-number
Displays the contents of the current running configuration file or the tunnel interface configuration. Example:
Router# show running-config interface tunnel 1
Building configuration...
Current configuration : 462 bytes
!
interface Tunnel1
ip address 192.0.2.1 255.255.255.0
no ip redirects
ip mtu 1440
ip nhrp authentication testing
ip nhrp group spoke_group2
ip nhrp network-id 123
ip nhrp holdtime 150
ip nhrp nhs dynamic nbma h1.cisco.com multicast
ip nhrp registration no-unique
ip nhrp registration timeout 10
ip nhrp shortcut
no ip route-cache cef
tunnel source Ethernet0/0
tunnel mode gre multipoint
tunnel key 1001
tunnel protection ipsec profile DMVPN
end
|
| Step 5 |
show
ip
nhrp
multicast
Displays NHRP multicast mapping information. Example:
Route# show ip nhrp multicast
I/F NBMA address
Tunnel1 192.0.2.1 Flags: nhs
|
Configuration Examples for DMVPN Configuration Using FQDN
- Example Configuring a Local DNS Server
- Example Configuring an External DNS Server
- Example Configuring NHS with a Protocol Address and an NBMA Address
- Example Configuring NHS with a Protocol Address and an FQDN
- Example Configuring NHS Without a Protocol Address and with an NBMA Address
- Example Configuring NHS Without a Protocol Address and with an FQDN
Additional References
Related Documents
MIBs
Technical Assistance
|
Description |
Link |
|---|---|
|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for DMVPN Configuration Using FQDN
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
| Table 1 | Feature Information for DMVPN Configuration Using FQDN |
|
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
DMVPN Configuration Using FQDN |
15.1(2)T |
The DMVPN Configuration Using FQDN feature enables the NHC to register with the NHS. It uses the NHRP without using the protocol address of the NHS. The following commands were introduced or modified: clear dmvpn session, debug nhrp condition, ip nhrp nhs,and ipv6 nhrp nhs. |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.