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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">It sounds like the VPN appliance is going to interfere with simply identifying the client by MAC, is that right?<br>
<br>
What is your DHCP lease time? You mention "if you connect three times in an hour, you get three leases" - does that mean your leases are good for an hour? (I don't think that's unreasonable for VPN, but it might be shorter than you want once this other issue
is worked out.)<br>
<br>
When you say you have more VPN clients, how many more? What percentage do you anticipate being connected at the same time? If you are increasing your number of clients and/or connected clients significantly, have you considered just increasing your VPN address
pool. You would not have to abandon the existing pool - you could create a shared network entry with a new subnet, creating a larger pool without having to restructure your existing IP scheme.<br>
<br>
Otherwise, I can't offer any guidance. I have not needed to resort to manipulation of client-id to assign addresses and do not know what your options are there.<br>
<br>
I really think I would be looking hard at the Cisco appliance to make sure you don't have an option to modify its behavior.<br>
<br>
All the best,<br>
Patrick<br>
<br>
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<div id="divRpF902396" style="direction: ltr;"><font size="2" face="Tahoma" color="#000000"><b>From:</b> dhcp-users [dhcp-users-bounces@lists.isc.org] on behalf of perl-list [perl-list@network1.net]<br>
<b>Sent:</b> Wednesday, November 23, 2016 7:42 AM<br>
<b>To:</b> Users of ISC DHCP<br>
<b>Subject:</b> Re: Change dhcp-client-identifier<br>
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<div style="font-family:Andale Mono; font-size:10pt; color:#000000">If you have foreknowledge of the MAC address, you could assign static IP based on the mac address like so:</div>
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<div style="font-family:Andale Mono; font-size:10pt; color:#000000">host SomeHost { hardware ethernet 00:01:02:03:04:05; fixed-address 10.0.10.2; }</div>
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<div style="font-family:Andale Mono; font-size:10pt; color:#000000">which would then make it not matter what their dhcp-client-identifier is...<br>
<br>
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<b>From: </b>"Thomas Zenz" <thomas.zenz@oenb.at><br>
<b>To: </b>dhcp-users@lists.isc.org<br>
<b>Sent: </b>Wednesday, November 23, 2016 7:08:55 AM<br>
<b>Subject: </b>Change dhcp-client-identifier<br>
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<blockquote style="border-left:2px solid #1010FF; margin-left:5px; padding-left:5px; color:#000; font-weight:normal; font-style:normal; text-decoration:none; font-family:Helvetica,Arial,sans-serif; font-size:12pt">
Sorry, I did not get the answer via mail, so I resend the Mail like this:<br>
<br>
Hi Patrick,<br>
<br>
I agree with you, that DHCP is not the cause of the issue. But, as<br>
allways, we are the ones who can fix it ;) Can we?<br>
<br>
We do have more VPN clients. That's why we had to look into this problem.<br>
<br>
Regards<br>
Thomas<br>
<br>
###################################################<br>
<br>
It sounds like something changed recently - new VPN appliance? More VPN<br>
clients?<br>
<br>
It might be useful to include that in the conversation because it<br>
doesn't sound like ISC DHCP is the cause of the issue, just where it's<br>
become visible.<br>
<br>
Patrick<br>
<br>
###################################################<br>
<br>
Dear all,<br>
<br>
We are running isc dhcp for years now.<br>
In the last weeks the count of vpn clients is growing. We only planned a<br>
/24 network. That would be ok if there wasn't the cisco logic of<br>
creating the dhcp-client-identifier. Cisco takes his own Mac-address,<br>
adds the PCName and here comes the problem, a random number...<br>
So my Client uses 17 Leases!<br>
I reduced the lease-time to 1h but still, if a usere reconnects 3 times<br>
in one hour, it uses 3 addreses.<br>
<br>
uid "\000cisco-881d.fc6f.affe-NB326973851-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973852-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973857-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973858-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973861-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973863-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973848-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973850-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973853-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973854-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973873-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973859-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973865-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973866-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973868-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973869-inside\000";<br>
uid "\000cisco-881d.fc6f.affe-NB326973870-inside\000";<br>
<br>
I tried to change the uid like this:<br>
on commit {<br>
set myClientID = pick (option dhcp-client-identifier,0);<br>
log (info, concat ("ClientID: ",myClientID));<br>
but it looks like the option is no string... (from the log)<br>
dhcpd: ClientID: HPs2,<br>
dhcpd: ClientID: HPs2,<br>
dhcpd: ClientID: fÚAi<br>
dhcpd: ClientID: HPsY<br>
dhcpd: ClientID: HPsW¬<br>
dhcpd: ClientID: lbmw&<br>
dhcpd: ClientID: lbmw&<br>
dhcpd: ClientID: HPsY<br>
dhcpd: ClientID: HPsY<br>
dhcpd: ClientID: HPsY<br>
dhcpd: ClientID: HPsY<br>
dhcpd: ClientID: HPs3T<br>
dhcpd: ClientID: HPsW¬<br>
dhcpd: ClientID: HPsW¬<br>
dhcpd: ClientID: HPs\<br>
dhcpd: ClientID: HPs\<br>
<br>
I tried to do it like this:<br>
if (binary-to-ascii(10,8,".",packet(24,3)) = "192.168.1" ) {<br>
set vpnClientID = concat(substring(myClientID,26,6),"-inside");<br>
set dhcp-client-identifier = vpnClientID;<br>
log (info, concat ("vpnClientID: ",vpnClientID));<br>
}<br>
This is also not working. I use a similar option to choose the PXE Bootfile.<br>
<br>
Please help<br>
Kind Regards<br>
Thomas<br>
<br>
<br>
<br>
_______________________________________________<br>
dhcp-users mailing list<br>
dhcp-users@lists.isc.org<br>
https://lists.isc.org/mailman/listinfo/dhcp-users</blockquote>
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