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Old 03-18-2013, 06:02 AM   #1
culin
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REgarding DHCP configuration


Hi all,

Am using RHEL 6. I have configured a dhcp server. But, What i need is "DHCP server SHOULD allocate DIFFERENT IP address" to the client when lease time expires. How can i do it ?

Regards,
Naren
 
Old 03-18-2013, 06:30 AM   #2
acid_kewpie
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That's not how DHCP works. You don't do this.
 
Old 03-18-2013, 06:39 AM   #3
culin
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But i can tell dhcp server to assign a static address right for a client ? likewise what i need is when an ip from the pool is allocated to a client and say i have set the max-lease-time 600; After 5 mins it should allocate a random IP from the pool instead it is allocating same IP to the client every time. Can't i override this option ?
 
Old 03-18-2013, 06:45 AM   #4
acid_kewpie
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no, it's not part of the DHCP RFC. A client should request to continue a lease half way through the lifetime of the lease, or more frequently. There is no reason for DHCP to explicitly change IP. You *could* in theory change the config to change an explicit reservation in the config, but this is nothing inherently to do with DHCP as a standard.

Whilst I can imagine lots of scenarios where it'd be "nice" to have this feature, it's not part of DHCP, and shouldn't be.
 
Old 03-18-2013, 07:54 AM   #5
asimba
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I guess you could automate it (though with few gotcha's)


But with those gotcha's and effort i am unsure its worth the time.
 
Old 03-18-2013, 08:41 AM   #6
culin
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Hi Chris,

Thanks for the info , I was going through this link

http://www.ntchosting.com/dns/dhcp.html

I don't know whether it is right or wrong. But, that mentions: A Dynamic allocation where a client will always have a random IP. Also in the below link (it might be specific to his own DHCP also am not sure)

http://osr600doc.sco.com/en/NET_tcp/dhcpC.dyn.html

It tells that

-- The DHCP server always assigns the address previously assigned to the client unless the address is unavailable. This caught my attention. In RFC it says,
"The server may choose the least recently assigned address" is this possible with RHEL 6 DHCP server or any 3rd party DHCP servers ?

All i want is DHCP server should assign a random IP (except the one assinged immediate past) to the client from the pool instead of allocating same IP every time for the client

Regards,
Naren
 
Old 03-18-2013, 09:04 AM   #7
acid_kewpie
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the server will choose the least recently assigned when ALL otehr eligible IP addresses are used. If there is an expired lease, then as much as it *could* be reallocated, logic says you might as well pick a new IP for a new client, incase that other expired client comes back again in the future. When there are no IP's left, logic then says that the lease that expired longest ago is probably fair game. So I really don't think that's the opportunity you think it is.
 
Old 03-19-2013, 02:15 AM   #8
culin
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oh ! okie thanks Chris,

I will try look into some customized servers and get exhausted and then give up !!

Regards,
Naren
 
  


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