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<p>The "static" in my previous mail means we put a IP into the lease file with a host declaration and a fixed-address, not mean the client with a static ip. This IP is in the middle of a dynamic range which is setting in dhcpd.conf.<br>
<br>
Giving the lease a long expired time is another choice for us, but there is still an error window if the client indeed down for a long time.<br>
<br>
<tt>So we would still want to know what exactly will happen if we put the dynamic ip which is in a dynamic ip range to be delared in the lease file by omapi?</tt><br>
<br>
<br>
<br>
Best Regards,<br>
<br>
--------------------------------------------------------------<br>
Wang Huazhong(Íõ»ªÖÒ)<br>
<br>
IBM CSTL HPC System Management Development<br>
Tel: 86-10-82452279<br>
Email: wanghuaz@cn.ibm.com<br>
Address: Ring Building 28,ZhongGuanCun Software Park,No.8 Dong Bei Wang West Road, Haidian District Beijing P.R.China 100193<br>
<br>
<br>
<img width="16" height="16" src="cid:1__=C7BBF247DF9F94F18f9e8a93df938@cn.ibm.com" border="0" alt="Inactive hide details for Glenn Satchell ---2011-04-14 19:18:42---Putting a static assignment in the middle of a dynamic range "><font color="#424282">Glenn Satchell ---2011-04-14 19:18:42---Putting a static assignment in the middle of a dynamic range is not a</font><br>
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<ul><b><font size="2">Glenn Satchell <glenn.satchell@uniq.com.au></font></b><font size="2"> </font><br>
<font size="2">Sent by: dhcp-users-bounces+wanghuaz=cn.ibm.com@lists.isc.org</font>
<p><font size="2">2011-04-14 19:17</font>
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<tr valign="top"><td width="168" bgcolor="#FFFFFF"><div align="center"><font size="2">Please respond to<br>
Users of ISC DHCP <dhcp-users@lists.isc.org></font></div></td></tr>
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<div align="right"><font size="2">To</font></div></td><td width="100%"><img width="1" height="1" src="cid:3__=C7BBF247DF9F94F18f9e8a93df938@cn.ibm.com" border="0" alt=""><br>
<font size="2">Users of ISC DHCP <dhcp-users@lists.isc.org></font></td></tr>
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<font size="2">Re: AW: DHCP configuration on RHEL6</font></td></tr>
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<tt>Putting a static assignment in the middle of a dynamic range is not a <br>
good plan. There are a number of ways that the dynamic ip could be <br>
re-assigned to a different client, for example the static client has <br>
icmp blocked by local firewall, so the dhcp server can't tell if the ip <br>
is already in use. If you have several thousand clients, then managing <br>
them becomes cumbersome.<br>
<br>
The way to ensure a dynamic IP is never reassigned is to ensure that <br>
there are always enough free IPs to cover the expected number of clients.<br>
<br>
What if you just used a really long lease time, maybe a few months or a <br>
year? That way the client would need to be down for a really long time <br>
before the address was re-assigned.<br>
<br>
-- <br>
regards,<br>
-glenn<br>
--<br>
Glenn Satchell | Miss 9: What do you<br>
Uniq Advances Pty Ltd, Sydney Australia | do at work Dad?<br>
</tt><tt><a href="mailto:glenn.satchell@uniq.com.au">mailto:glenn.satchell@uniq.com.au</a></tt><tt> | Miss 6: He just<br>
</tt><tt><a href="http://www.uniq.com.au">http://www.uniq.com.au</a></tt><tt> tel:0409-458-580 | types random stuff.<br>
<br>
On 04/14/11 07:50, Rainer Stumbaum wrote:<br>
> Hi,<br>
><br>
> you could check if the infinite-is-reserved statement does what you require.<br>
><br>
> Best regards<br>
> Rainer<br>
><br>
> --- Hua Zhong Wang /<wanghuaz@cn.ibm.com>/ schrieb am *Mi, 13.4.2011:<br>
><br>
><br>
> Von: Hua Zhong Wang <wanghuaz@cn.ibm.com><br>
> Betreff: DHCP configuration on RHEL6<br>
> An: dhcp-users@lists.isc.org<br>
> Datum: Mittwoch, 13. April, 2011 18:28 Uhr<br>
><br>
> Hi,<br>
><br>
> We are working on a solution to manage large clusters, there will be<br>
> thousands of clients requesting dynamic IP address from dhcp server,<br>
> and on each client, there are several services that are working and<br>
> heavily depending on the dynamic ips.<br>
><br>
> We know that the dynamic ip addesses on each client generally will<br>
> not be changed, except the client is down for a long time and dhcp<br>
> server re-use the expired leases.<br>
><br>
> But once this happens, it will take lots of effort to reconfigure<br>
> the client based on the dynamic ip on the client.<br>
><br>
> So we are trying to find a way to guarantee the ip address on clients<br>
> will never be changed. Static ip address with a host declaration in<br>
> lease file or dhcpd.conf could help it. But this way needs us to<br>
> firstly assign a dynamic ip to the clients, and commnunicate with the<br>
> clients to get their mac addresses, then write a host declaration<br>
> with a new ip/mac into lease file or dhcpd.conf. And with this<br>
> configuration, properly we need to prepare two ips to each client,<br>
> one ip range for dynamic ips and another ip for static. Also it<br>
> needs the clients to reset their adapters to switch from dynamic ips<br>
> to static ips.<br>
><br>
> This procedure is a little complicated especially for managing a<br>
> large cluster, we are trying to simplify it, one proposal would be<br>
> just to write the dynamic ip that is inside the dynamic range into<br>
> the lease file or dhcpd.conf with a host declaration, to make the<br>
> dynamic range to be static. Several benefits: it doesn't need two<br>
> ips per client, doesn't need to assign new static ip by admin<br>
> manually, and don't need to reset client's adapters. We got some<br>
> message that dhcp server doesn't like users to do so, so I would<br>
> know the answer to the following question:<br>
><br>
> What exactly will happen if we put the dynamic ip which is in a<br>
> dynamic ip range to be static with fixed-address? Is this way<br>
> acceptable by dhcp server and stable enough?<br>
><br>
><br>
><br>
><br>
> Best Regards,<br>
><br>
> --------------------------------------------------------------<br>
> Wang Huazhong(Íõ»ªÖÒ)<br>
><br>
> IBM CSTL HPC System Management Development<br>
> Tel: 86-10-82452279<br>
> Email: wanghuaz@cn.ibm.com<br>
> Address: Ring Building 28,ZhongGuanCun Software Park,No.8 Dong Bei<br>
> Wang West Road, Haidian District Beijing P.R.China 100193<br>
><br>
><br>
<br>
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