udp broadcast across vlans

[tung.dang]

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.

[jkillion]

Yes, you can forward UDP broadcast's across VLAN's.

http://www.cisco.com/en/US/docs/internetworking/case/studies/cs006.html

[tung.dang]

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]

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

[tung.dang]

Still doesn't work. We are running hsrp, could this be the reason?

Thanks.