home

Supported Platforms

Getting startedVyatta NOS OverviewVyatta NOS Architecture OverviewSupported PlatformsRelease Notes
search
search
Getting startedVyatta NOS OverviewVyatta NOS Architecture OverviewSupported PlatformsRelease Notes

Vyatta Network OS Documentation

Learn how to install, configure and operate the Vyatta NOS, which helps drive our virtual networking & physical platforms portfolio.

search
thumbnail

Supported Platforms

Supported Platforms Contents

close
  • close

    vRouter

    • close

      Configuration (vRouter)

      • close

        System and Services

        • close

          Services

          • close

            DNS

            • DNS configuration examples

  • VNF

  • UfiSpace S9500-30XS

  • UfiSpace S9700-53DX

  • EdgeCore 5916-54XKS

  • Physical uCPEs

  • Distributed Services Platform

  1. Supported Platforms
  2. arrow_right
  3. vRouter
  4. arrow_right
  5. Configuration (vRouter)
  6. arrow_right
  7. System and Services
  8. arrow_right
  9. Services
  10. arrow_right
  11. DNS

list_altShow Contents

list_altShow Page Sections

chevron_left

thumbnailSupported Platforms

DNS

chevron_right
DNS configuration examples

This section presents the following topics:

  • Configuring access to a name server
  • Configuring dynamic DNS
  • Configuring DNS forwarding
  • Statically configured entries and DNS forwarding
Configuring access to a name server

To be able to translate host names (such as www.brocade.com) to IP addresses (such as 69.59.150.141), the system must be able to access a DNS server.

Configuring access to a DNS server is a function of basic system management, and is described in Ciena Vyatta Network OS Basic System Configuration Guide. For your convenience, the configuration example is repeated here.

Configuring static access to a DNS name server configures a static IP address for the DNS server at address 12.34.56.100. To configure the vRouter in this way, perform the following steps.

Configuring static access to a DNS name serverStepCommandSpecify the IP address of the DNS server. vyatta@R1# set system name-server 12.34.56.100

Configuring dynamic DNS

Dynamic DNS shows a typical DDNS scenario. In this scenario:

  • The vRouter (R1) is connected to an ISP via dp0p1p1.
  • The network domain is company.com.
  • The vRouter host name is r1.company.com.
  • The web server of the company is located behind the vRouter. Its host name is www.company.com.
  • The ISP is providing dynamic IP addresses to its clients through DHCP.
  • The IP address of the dp0p1p1 interface in the vRouter changes over time because of the dynamic assignment by the ISP.
  • The web server of the company is behind a Network Address Translation (NAT) device on the vRouter, so its IP address (as viewed from the Internet) changes when the ISP assigns a new address to the dp0p1p1 interface.
  • Because the web address of the server changes, responses to DNS queries for www.company.com must also change to the new IP address. DDNS resolves this problem.

DDNS allows the vRouter (R1) to update the DNS system with the new IP address information for any local host names (for example, r1.company.com, and www.company.com) whenever the IP address on dp0p1p1 changes. The setup process is as follows:

Sign up for DDNS service from one of the supported service providers: DNS Park: www.dnspark.com DSL Reports: www.dslreports.com DynDNS: www.dyndns.com easyDNS: www.easydns.com namecheap: www.namecheap.com Sitelutions: www.sitelutions.com zoneedit: www.zoneedit.com

The individual providers offer instructions for sign-up. Depending on the service provider, host names may need to include the domain name (for example, www instead of www.company.com).

Configure the vRouter (R1 in the example) with service provider information such as the service name, a login ID, and a password so that the system can determine how to log on and send updates to the DDNS service provider. Configure the vRouter with the host names that must be updated in the DNS system when the IP address on dp0p1p1 changes.
Setting up Dynamic DNS

Dynamic DNS

The following example shows how to set up DDNS for DDNS service provider DynDNS. It is assumed for this example that you have already signed up with DynDNS). To configure the vRouter in this way, perform the following steps in configuration mode.

Setting up dynamic DNS Step Command Set the service provider. vyatta@R1# set service dns dynamic interface dp0p1p1 service dyndns Set the DDNS service provider login ID (for example, vtest). vyatta@R1# set service dns dynamic interface dp0p1p1 service dyndns login vtest Set the DDNS service provider password (for example, testpwd). vyatta@R1# set service dns dynamic interface dp0p1p1 service dyndns password testpwd Specify R1 as a host name whose DNS entry needs to be updated when the IP address on dp0p1p1 changes. vyatta@R1# set service dns dynamic interface dp0p1p1 service dyndns host-name r1.company.com Specify www as a host name whose DNS entry needs to be updated when the IP address on dp0p1p1 changes. vyatta@R1# set service dns dynamic interface dp0p1p1 service dyndns host-name www.company.com Commit the changes. vyatta@R1# commit OK Show the dynamic DNS configuration. vyatta@R1# show service dns dynamic interface dp0p1p1 { service dyndns { host-name r1.company.com host-name www.company.com login vtest password testpwd } }

At this point, whenever the IP address on dp0p1p1 changes, the vRouter automatically logs onto the DynDNS service by using the vtest login ID and the testpwd password. It sends an update for the r1.company.com and www.company.com host names specifying the new IP address required to reach those hosts on the company.com domain. External users that query DNS for r1.company.com or www.company.com are subsequently answered with the new address from the DNS system.

Dynamic DNS updates are logged. To see the updates, set up logging by using the system syslog global facility facility level level command, where facility is daemon and level is notice. See Ciena Vyatta Network OS Basic System Configuration Guide for details.
Configuring DNS forwarding

Configuring the vRouter for DNS forwarding has two main steps:

Specifying the DNS name servers to which to forward Specifying the interfaces on which to listen for DNS requests
Specifying DNS Name Servers

Name server locations can be obtained in three ways:

  • From the system name server list, defined by using the set system name-server command
  • By DHCP
  • By listing additional name servers by using service dns forwarding dhcp <interface>

By default, the vRouter forwards DNS requests to name servers on the system name server list plus name servers obtained through DHCP. You can override the default behavior by specifying any or all of the following:

  • Specifically use system-defined name servers. To do this, use service dns forwarding system.
  • Specifically use name servers received for the interface that is using DHCP client to get an IP. To do this, use service dns forwarding dhcp <interface>.
  • List additional name servers by using service dns forwarding name-server <ipv4>.

These three options can be used in any combination; however, using any of them eliminates the default DNS forwarding behavior.

When DNS forwarding starts or restarts, it broadcasts a message to all the name servers in the pool and selects the first name server to answer. This name server is used unless it becomes unreachable, in which case the system sends another broadcast message to the remaining name servers in the pool.

Specifying the Listening Interfaces

The listening interfaces are the interfaces to which internal clients forward DNS requests. The DNS forwarding service listens for these requests and forwards them to the name server.

To set the listening interface, use service dns forwarding listen-on <interface>. You can specify more than one interface by issuing this command multiple times.

DNS Forwarding Scenario

After these steps are completed, DNS forwarding is set up. At this point, the vRouter DHCP server can be used to distribute the DNS forwarding interface address to DHCP clients. (For information about setting up a DHCP server on the vRouter, see DHCP .

Scenario using DNS forwarding

close

Contents

  • Configuring access to a name server

  • Configuring dynamic DNS

    • Setting up Dynamic DNS

  • Configuring DNS forwarding

    • Specifying DNS Name Servers

    • Specifying the Listening Interfaces

    • DNS Forwarding Scenario

  • Statically configured entries and DNS forwarding

Last updated: May 7, 2021

chevron_leftchevron_right

Helpful Links

Feedback

Privacy Policy

Contact Us

Key Resources

Get Started An introduction to the Ciena Vyatta NOS

The Vyatta NOS Overview Get to know more about how Vyatta NOS is the best solution

Vyatta NOS Architecture Overview An overview of the Vyatta NOS system architecture

Troubleshooting Guide Identify common issues with your configuration and network setup

© 2022 Ciena Intellectual Property, All rights reserved