Vyatta Network OS Documentation

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

VRF support for DNS

The vRouter uses DNS in both the client (resolver) and server (proxy) roles. You can configure DNS for individual routing instances. If you configure DNS without specifying a routing instance, the default routing instance is used.

For DNS client (resolver) operations, configure DNS name servers when creating a new routing instance to support DNS clients and dynamic synchronization. As a client, a set of name server addresses is used to resolve queried domain names and update DNS records dynamically.

The following example shows how to configure the 10.70.20.23 DNS name server for the default routing instance.
vyatta@R1# set system name-server 10.70.20.23
vyatta@R1# commit
vyatta@R1# run show configuration
system {
	name-server 10.70.20.23
}

The following example shows the same configuration sequence for the BLUE routing instance.

vyatta@R1# set routing routing-instance BLUE system name-server 10.70.20.23
vyatta@R1# commit
vyatta@R1# run show configuration
routing {
        routing-instance BLUE {
                system {
                        name-server 10.70.20.23
                }
        }
}

For server (proxy) operations, if the queried record is not in the cache, the vRouter sends the query to DNS servers that are listed in the name server list for the specified routing instance. This name server list can apply to each DNS forwarding instance when configuring DNS forwarding. If not configured, the routing-instance-specific name servers that are configured are used.

The following example shows how to configure proxy settings (listen-on interface dp0s4 and cache size 1024) for the default routing instance.
vyatta@R1# set service dns forwarding listen-on dp0s4
vyatta@R1# set service dns forwarding cache-size 1024
vyatta@R1# commit
vyatta@R1# run show configuration
service {
        dns {
                forwarding {
                        cache-size 1024
                        listen-on dp0s3
                }
        }
}

The following example shows the same configuration sequence for the BLUE routing instance.

vyatta@R1# set routing routing-instance BLUE service dns forwarding listen-on dp0s4
vyatta@R1# set routing routing-instance BLUE service dns forwarding cache-size 1024
vyatta@R1# commit
vyatta@R1# run show configuration
routing {
        routing-instance BLUE {
                service {
                        dns {
                                forwarding {
                                        cache-size 1024
                                        listen-on dp0s4
                                }
                        }
                }
	       }
}

For more information about DNS and configuring DNS, see Ciena Vyatta Network OS Basic System Configuration Guide .