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Which VLAN to enable ARP inspection

Which VLAN   to enable ARP inspection

I would like to know which VLAN to enable ARP Inspection. Is it going to be on the same VLAN where the Trusted DHCP server resides on ?
Or on every VLAN in the network ?

Switch(config)#ip arp inspection vlan <VLAN Name>



I also wants to know about the DHCP Option 82 configuration.
Using IP helper-address <IP address> is enough or  we need to add:
ip dhcp relay information option

Thank you
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Chris Swinney
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Craig Beck
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ARP inspection needs to be used in conjunction with DHCP snooping, and is usually used on client VLANs.  It won't work without DHCP snooping.

If you have a DHCP server on a server VLAN, for example, while clients are on a client VLAN, just enable ARP inspection on the client VLAN.

Disable option-82.  It'll same you hours of troubleshooting if it's turned off.
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jskfan
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ASKER

Craig Beck

Let 's the DHCP server is on VLAN 66.
Computers can be in any VLAN.
So where do you apply arp inspection ? Since there so many Vlans in the Network.
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Craig Beck
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Apply to any VLAN where clients can connect.
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jskfan
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ASKER

Craig Beck

So If we have 100 Vlans in the Network.. we'll still have to  to go to each Vlan and type:

Switch(config)#ip arp inspection vlan <VLAN Name>
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Craig Beck
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ASKER

OK.. Thank you very Much ,  Craig