Switch Management Commands 1959ip name-server source-interfaceUse the ip name-server source-interface command to select the interfacefrom which to use the IP address in the source IP address field of transmittedDNS packets. To revert to the default IP address, use the no form of thiscommand.Syntaxip name-server source-interface {loopback loopback-id | tunnel tunnel-id |vlan vlan-id }no ip name-server source-interface• loopback-id— A loopback interface identifier.• tunnel-id— A tunnel identifier.• vlan-id— A VLAN identifier.Default ConfigurationBy default, the switch uses the assigned switch IP address as the source IPaddress for DNS packets. This address is either the IP address assigned to theVLAN from which the DNS packet originates or the out-of-band interface IPaddress.Command ModeGlobal Configuration modeUser GuidelinesThe source interface must have an assigned IP address (assigned eithermanually or via another method such as DHCP).The use of a source interface allows firewalls devices to identify DNS packetsas coming from a specific switch. If the source interface is not specified, theprimary address of the outbound interface is used as the source interface. Ifthe specified interface is down, the DNS client falls back to it’s original(unconfigured) behavior.
