secondary ip with helper-address

Unanswered Question
Jul 25th, 2007

I have a router with an ip address and a secondary ip. In that interfaces there is a helper-adress to redirec de broadcast to dhcp server.

Is any way to redirec only broacast from de primary interface ip address?



I have this problem too.
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sundar.palaniappan Wed, 07/25/2007 - 10:40


I don't think you can filter dhcp request from some hosts while forwarding the other requests to the dhcp server. The router would forward all dhcp requests to the server address identified in the 'ip helper address' command using the primary interface IP as the source of the packets.

Have you thought about assigning static address to all the hosts in the secondary subnet to address this problem.



Richard Burts Wed, 07/25/2007 - 12:47


In addition to the good points that you made I believe that there is one other aspect to consider about the request to "redirec only broacast from de primary interface ip address". All DHCP requests have a source address of all zero (since they are asking for assignment of an IP address they do not yet have an address). So there will be no broadcasts from addresses in the primary subnet.




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