# VLAN and ARP broadcast



## horesh99 (Jul 1, 2013)

how an ARP broadcast (say from a router) gets into all vlans of a network?


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## Fjandr (Sep 26, 2012)

You can use proxy-arp to broadcast to non-local network segments (in this case, another VLAN).


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## horesh99 (Jul 1, 2013)

Fjandr said:


> You can use proxy-arp to broadcast to non-local network segments (in this case, another VLAN).


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## horesh99 (Jul 1, 2013)

10x but still how does it work?
generally Vlans blocks broadcasts. therefore how a broadcast of any type overpasss this vlan bocking swiches?
is there a way to use a configuer "allow broadcasts from specicfic MAC address or IP address?


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## Fjandr (Sep 26, 2012)

Your hardware has to support proxy-arp. It's a method for forwarding an ARP broadcast to a non-local network segment.


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## Wand3r3r (Sep 17, 2010)

Vlans don't block broadcasts. That is a misunderstanding. You use vlans to limit broadcasts to just their vlan domain similar to when you use subnetting to limit the ip broadcast domain.

Routers are used to by arp to get addresses on the other side.
Address Resolution Protocol (ARP): TCP/IP

Proxy arp devices can do similar
http://en.wikipedia.org/wiki/Proxy_ARP


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