Ip-helper question

Unanswered Question
Mar 16th, 2009

Hi all,

We have two ip-helper on our vlan 5.

It seems to take the first one every time and the DHCP scope are always full.

Any sugestion what we should do?

interface Vlan5

ip address

ip helper-address

ip helper-address

Regards Jan

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Jon Marshall Mon, 03/16/2009 - 03:23


The router/L3 switch uses both ip-helper's at the same time so it will forward a request to both DHCP servers. If you have split the scope for vlan 5 across both servers then it shouldn't matter if the first one has run out as the client will receive an offer from the second DHCP server.


Jan Rockstedt Mon, 03/16/2009 - 03:27



ip helper-address = - 254

ip helper-address = - 254

So it use both every time for request ip number... strange... why the 41 is full every time.


Jon Marshall Mon, 03/16/2009 - 03:37


Usually the client will use the first DHCP offer it gets. Is there any difference between the servers in terms of

1) CPU usuage

2) Memory

3) Network utilisation on the NIC.

Perhaps the .41 server is just a faster server to respond.



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