Udp Helper With No Configured Broadcast Addresses; Troubleshooting Udp Helper - Dell Force10 Z9000 Configuration Manual

Packet 2 is sent from a host on VLAN 101. It has broadcast MAC address and a destination IP address that matches the configured
broadcast address on VLAN 101. In this case, Packet 2 is flooded on VLAN 101 with the destination address unchanged because the
forwarding process is Layer 2. If you enabled UDP helper, the packet is flooded on VLAN 100 as well.
Figure 40. UDP Helper with Configured Broadcast Addresses

UDP Helper with No Configured Broadcast Addresses

The following describes UDP helper with no broadcast addresses configured.
• If the incoming packet has a broadcast destination IP address, the unaltered packet is routed to all Layer 3 interfaces.
• If the Incoming packet has a destination IP address that matches the subnet broadcast address of any interface, the unaltered
packet is routed to the matching interfaces.

Troubleshooting UDP Helper

To display debugging information for troubleshooting, use the debug ip udp-helper command.
Example of the debug ip udp-helper Command
Dell(conf)# debug ip udp-helper
01:20:22: Pkt rcvd on Te 5/1 with IP DA (0xffffffff) will be sent on Te 5/2 Te 5/3 Vlan 3
01:44:54: Pkt rcvd on Te 7/1 is handed over for DHCP processing.
When using the IP helper and UDP helper on the same interface, use the debug ip dhcp command.
Example Output from the debug ip dhcp Command
Packet 0.0.0.0:68 -> 255.255.255.255:67 TTL 128
2005-11-05 11:59:35 %RELAY-I-PACKET, BOOTP REQUEST (Unicast) received at interface
172.21.50.193 BOOTP Request, XID = 0x9265f901, secs = 0 hwaddr = 00:02:2D:8D:46:DC,
giaddr = 0.0.0.0, hops = 2
2005-11-05 11:59:35 %RELAY-I-BOOTREQUEST, Forwarded BOOTREQUEST for 00:02:2D:8D:46:DC
to 137.138.17.6
2005-11-05 11:59:36 %RELAY-I-PACKET, BOOTP REPLY (Unicast) received at interface
194.12.129.98 BOOTP Reply, XID = 0x9265f901, secs = 0 hwaddr = 00:02:2D:8D:46:DC,
giaddr = 172.21.50.193, hops = 2
331
IPv4 Routing