Configuring IP Directed Broadcast for Switches
This task uses Junos OS for EX Series switches that does not support the Enhanced Layer 2 Software (ELS) configuration style. If your switch runs software that supports ELS, see Configuring IP Directed Broadcast for Switches. For ELS details, see Using the Enhanced Layer 2 Software CLI.
You can use IP directed broadcast on an EX Series switch to facilitate remote network management by sending broadcast packets to hosts on a specified subnet without broadcasting to the entire network. IP directed broadcast packets are broadcast on only the target subnet. The rest of the network treats IP directed broadcast packets as unicast packets and forwards them accordingly.
Before you begin to configure IP directed broadcast:
Ensure that the subnet on which you want broadcast packets using IP direct broadcast is not directly connected to the Internet.
Configure a routed VLAN interface (RVI) for the subnet that will be enabled for IP direct broadcast. For EX Series, see Configuring Routed VLAN Interfaces on Switches (CLI Procedure). For QFX Series, seeConfiguring Integrated Routing and Bridging Interfaces on Switches (CLI Procedure) or Configuring VLANs on Switches with Enhanced Layer 2 Support.
We recommend that you do not enable IP directed broadcast on subnets that have a direct connection to the Internet because of increased exposure to denial-of-service (DoS) attacks.
To enable IP directed broadcast for a specified subnet:
In a mixed Virtual Chassis, when you configure targeted broadcast, you can only configure one interface. Otherwise, targeted broadcast will not work.
- Add the target subnet’s logical interfaces to the
user@switch# set ge-0/0/0.0 family ethernet-switching vlan members v1
user@switch# set ge-0/0/1.0 family ethernet-switching vlan members v1
- Configure the Layer 3 interface on the VLAN that is the
target of the IP directed broadcast packets:
user@switch# set vlan.1 family inet address 10.1.2.1/24
- Associate a Layer 3 interface with the VLAN:
user@switch# set v1 l3-interface vlan.1
- Enable the Layer 3 interface for the VLAN to receive IP
user@switch# set vlan.1 family inet targeted-broadcast