udp broadcast across vlans

Unanswered Question
May 25th, 2010
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Hi,


We have an application seeking for all testing equipment device on UDP port 43968 but it doesn't seems to work in our network. Would ip helpder-address can help? our core switch is 6509. please advice


Thanks.

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tung.dang@finis... Tue, 05/25/2010 - 16:43
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Hello,


I have entered ip forward-protocol udp 43968 on both core (6905) but still doesn't work. Am I missing anything here? Thanks

Jon Marshall Tue, 05/25/2010 - 17:20
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tung.dang@finisar.com


Hello,


I have entered ip forward-protocol udp 43968 on both core (6905) but still doesn't work. Am I missing anything here? Thanks


If you want to forward udp broadcasts at L3 you need to do 3 things -


1) configure an ip helper-address to point to the remote subnet broadcast address

2) configure the ip forward-protocol command

3) configure "ip directed-broadcast" on the receiving vlan interface


so as an example, vlan 10 is the source of UDP broadcasts and vlan 11 is the vlan receiving the udp broadcast. vlan 11 subnet is 192.168.5.0/24


int vlan 10

ip helper-address 192.168.5.255

ip forward-protocol udp 43968


int vlan 11

ip directed-broadcast


Jon

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