change ip address every 6 hours

[Tom Martinson]

Two things.

1.  You can do this by changing having a couple of dhcp.conf files and 
change the files from time to time.  Just do a cron entry for this.

2.  This will not solve your problem.  All your customer needs to do is 
sign up for one of the free Dynamic DNS services.  Even new personal 
home routers from makers like (Linksys, dlink, netgear, ect. ) have 
automatic DDNS updates on it.

Basically this is not how you want to solve this issue.  What are you 
using to deliver service, WiMAX, DSL, Cable?  If you are using Cable 
Modems you should just edit the modem config file to filter off incoming 
ports that you want to block.

Tom

On 02/15/2012 03:00 AM, Yannick CHAMPS wrote:
> Our "legitimate" reason is : we want to charge subcribers for fixed ip
> address service.
> So others must have their ip addresses changed regularly.
>
> Can I have some details about external scripting you mentioned earlier ?
>
>
> Le 14/02/2012 21:38, Simon Hobson a écrit :
>> Yannick CHAMPS wrote:
>>
>>> could you kindly share a sample of dhcpd.conf which changes randomly
>>> subscribers ip addresses every 6 hours ?
>> No, because it's not supported. It is expressly against the RFCs which
>> require the server to try and give a client the same IP address each
>> time it connects - subject to it not having been given to a different
>> client since it last had a lease.
>> Bear in mind that it breaks so many things. To start with, all
>> sessions that a customer has open (perhaps a download that's got 5
>> minutes left but has been running for 2 hours) will break. That alone
>> is good enough reason not to do it.
>>
>> There are ways to "sort of" simulate this - but they all require
>> external scripting to modify the config file periodically.
>>
>>
>> Must admit, it's not come up for some time - the usual response is
>> "check the archives, it comes up regularly - and no we won't help you
>> break things that badly" (or something to that effect).
>>
>> Do you have a specific reason for needing to do this ? Other than a
>> manager telling you that he needs customers to keep changing IP
>> address to make it hard to run servers at home. Such an attempt is a
>> waste of time - there are many dynamic DNS servers out there that will
>> "fix" that problem.
>>
>> I think we only saw one legitimate reason in all the times this came
>> up. All the rest were "my manager needs me to break the network and
>> p**s off our customers". To the latter, the response is "go find
>> another job, your customers will get p**ssed off and move to a decent
>> ISP - and your's will go bust".
>>
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