BigIron RX Series Configuration Guide 18753-1001810-01Configuring forwarding parameters 7To modify the TTL threshold to 25, enter the following commands.BigIron RX(config)# ip ttl 25Syntax: ip ttl <1-255>Enabling forwarding of directed broadcastsA directed broadcast is an IP broadcast to all devices within a single directly-attached network orsubnet. A net-directed broadcast goes to all devices on a given network. A subnet-directedbroadcast goes to all devices within a given subnet.NOTEA less common type, the all-subnets broadcast, goes to all directly-attached subnets. Forwarding forthis broadcast type also is supported, but most networks use IP multicasting instead of all-subnetbroadcasting.Forwarding for all types of IP directed broadcasts is disabled by default. You can enable forwardingfor all types if needed. You cannot enable forwarding for specific broadcast types.To enable forwarding of IP directed broadcasts, enter the following command.BigIron RX(config)# ip directed-broadcastSyntax: [no] ip directed-broadcastBrocade software makes the forwarding decision based on the router's knowledge of thedestination network prefix. Routers cannot determine that a message is unicast or directedbroadcast apart from the destination network prefix. The decision to forward or not forward themessage is by definition only possible in the last hop router.To disable the directed broadcasts, enter the following command in the CONFIG mode.BigIron RX(config)# no ip directed-broadcastTo enable directed broadcasts on an individual interface instead of globally for all interfaces, entercommands such as the following.BigIron RX(config)# interface ethernet 1/1BigIron RX(config-if-e10000-1/1)# ip directed-broadcastSyntax: [no] ip directed-broadcastDisabling forwarding of IP source-routed packetsA source-routed packet specifies the exact router path for the packet. The packet specifies the pathby listing the IP addresses of the router interfaces through which the packet must pass on its way tothe destination. The device supports both types of IP source routing:• Strict source routing – requires the packet to pass through only the listed routers. If the devicereceives a strict source-routed packet but cannot reach the next hop interface specified by thepacket, the device discards the packet and sends an ICMP Source-Route-Failure message tothe sender.NOTEThe device allows you to disable sending of the Source-Route-Failure messages. Refer to“Disabling ICMP messages” on page 188.
