change ip address every 6 hours

[Yannick CHAMPS]

1. Sorry, but what do I have to modify in the different dhcpd.conf files
to make ip change happens ?

2. of course DDNS will update but your current IP sessions (vpn,
download...)will terminate during the IP change operation



Le 14/02/2012 22:08, Tom Martinson a écrit :
> 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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