Broadcast between VLANs

Unanswered Question
Nov 4th, 2007

Hi All,

I have a scenario where i want to pass specific broadcasts from one server in one VLAN to other Servers (multiple servers) in other vlan.

I have a 3750 switch connected to a router. on my switch there exist 3 vlans.

as said, how can i pass broadcasts generated by one server in vlan A to some machines in vlan B ?

I have checked the forum for something similar and i have come up with the followin `solutions`:

A. Use trunks .

how can this work out ? is the traffic supposed to be directed to the router and then back to the other vlan. Will i require multiple trunks and interfaces ???

B. Using ip helper and ip directed broadcast commands

Will these commands work on Vlans as they work on router interfaces ???

also what in your opinion is the best way to achieve this and can you please give me a sample configuration for the affected devices ???

Thanks all,


I have this problem too.
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ohassairi Mon, 11/05/2007 - 02:14

use the second solution. it works with vlan as with router interfaces.

for example we can allow dhcp request (broadcast) to be directed to dhcp server that is in an other vlan.

please rate if it helps

g-serghiou Mon, 11/05/2007 - 02:31

hi ohassari,

so i will go with second option.

i will need to specify ip addresses for each vlan, as i do with vlan1 , and then issue my ip-helper related commands under each vlan to allow broadcasts to IPs on other vlans????



g-serghiou Mon, 11/05/2007 - 03:15


i will try it and will let you know if i have any problems




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