AW: DHCP configuration on RHEL6

Rainer Stumbaum stumbaumr at
Wed Apr 13 21:50:39 UTC 2011


you could check if the infinite-is-reserved statement does what you require.

Best regards

--- Hua Zhong Wang <wanghuaz at> schrieb am Mi, 13.4.2011:

Von: Hua Zhong Wang <wanghuaz at>
Betreff: DHCP configuration on RHEL6
An: dhcp-users at
Datum: Mittwoch, 13. April, 2011 18:28 Uhr


We are working on a solution to manage large clusters, there will be thousands of clients requesting dynamic IP address from dhcp server, and on each client, there are several services that are working and heavily depending on the dynamic ips.  

We know that the dynamic ip addesses on each client generally will not be changed, except the client is down for a long time and dhcp server re-use the expired leases.  

But once this happens, it will take lots of effort to reconfigure the client based on the dynamic ip on the client.

So we are trying to find a way to gurantee the ip address on clients will never be changed. Static ip address with a host declaration in lease file or dhcpd.conf could help it. But this way needs us to firstly assign a dynamic ip to the clients, and commnunite with the clients to get their mac addresses, then write a host declaration with a new ip/mac into lease file or dhcpd.conf.  And with this  configuration, properly we need to prepare two ips to each client, one ip range for dynamic ips and another ip for static.  Also it needs the clients to reset their adapters to switch from dynamic ips to static ips.

This procedure is a little complicated expecially for managing a large cluster, we are trying to simplify it, one proposal would be just to write the dynamic ip that is inside the dynamic range into the lease file or dhcpd.conf with a host declaration, to make the dynamic range to be static.  Several benifits: it doesn't need two ips per client, doesn't need to assign new static ip by admin manually, and don't need to reset client's adapters.  We got some message that dhcp server doesn't like users to do so, so I would know the answer to the following question:

What exactly will happen if we put the dynamic ip which is in a dynamic ip range to be static with fixed-address?  Is this way acceptable by dhcp server and stable enough?

Best Regards,


Wang Huazhong(王华忠)

IBM CSTL HPC System Management Development

Tel: 86-10-82452279

Email: wanghuaz at

Address: Ring Building 28,ZhongGuanCun Software Park,No.8 Dong Bei Wang West Road, Haidian District Beijing P.R.China 100193

-----Integrierter Anhang folgt-----

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