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<font size="-1">I again strongly suggest that you rethink this
course of action. But if you still want to do it. I would
suggest that you read up on how ISC DHCP servers work, or hire a
consultant. <br>
<br>
Now once customers realize what you are doing, how are you
planning on solving the problem when people just simply get a
lease and statically assign their IP addresses? When that starts
to happen you will have some major issues. <br>
<br>
I can not stress enough how badly things are going to go wrong if
you take this course of action.<br>
<br>
Tom<br>
</font><br>
On 02/15/2012 03:27 AM, Yannick CHAMPS wrote:
<blockquote cite="mid:4F3B6C68.8040402@viti.pf" type="cite">
<pre wrap="">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 :
</pre>
<blockquote type="cite">
<pre wrap="">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:
</pre>
<blockquote type="cite">
<pre wrap="">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 :
</pre>
<blockquote type="cite">
<pre wrap="">Yannick CHAMPS wrote:
</pre>
<blockquote type="cite">
<pre wrap="">could you kindly share a sample of dhcpd.conf which changes randomly
subscribers ip addresses every 6 hours ?
</pre>
</blockquote>
<pre wrap="">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".
</pre>
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