migrate from remotely located to central servers

Bill Shirley bill at c3po.polymerindustries.biz
Thu Jul 30 13:51:19 UTC 2020

ISC documentation: https://kb.isc.org/docs/isc-dhcp-44-manual-pages-dhcp-options

Looks like your domain-name-servers option is incorrect:
option domain-name-servers, *8.8*.4.4;

Add this to your log statement to see the options requested:
     "  ReqOpt:", pick-first-value(binary-to-ascii(10, 8, ",", option dhcp-parameter-request-list), "(none)"),
Make sure the client is requesting option 66.  BTW, if the dhcpd encounters a null
in the log text, it will truncate the rest of the line.  That's why I use 'pick-first-value' a lot.

If it's not requesting option 66, you might try forcing the option.  I've never used this:
if exists dhcp-parameter-request-list {
# Always send the local-pac-server (252) option (specified in hexadecimal, ie: 252 = 0xfc)
     option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list, fc);

I have used this to replace the entire requested option list:
option dhcp-parameter-request-list = 01: 03: 06: 0c: 0f: 1c: 2a;


On 7/29/2020 7:45 PM, Jason Brooks wrote:
> Hello Bill,
> At first I didn't understand, but now I do. Once I defined the pool denying class members, I was able to get ip addresses in 
> the 192.168.188.range. Thanks!
> I began to run "dhcpd -d" and playing with the log output to see if my substring statements were even making sense.
> So with the circuit id substring statements, I wasn't comparing correctly.  It's not clear why 3.0.4 worked this way.  I 
> needed the two bytes on the far right side of the circuit id...thus
> the lines:
>      "and ( substring (option agent.circuit-id,2,2)="\x01\x2C" )"
> became:
>      "and ( suffix ( option agent.circuit-id, 4) ="012C" )"
> note the use of suffix rather than substring and the lack of "\x" inside the double quotes.
> So my next issue here is in the RegionX-BOOT-CPE-MODELx class declaration, tftp-server-name is not being returned. Whereas the 
> boot filename is.  Why not? Based on what I found 'tftp-server-name" should correspond to dhcp option 66: defined in rfc2132.
> I have noticed that it's hard to figure out which isc dhcpd options map to those defined in the rfcs.  I found THIS table 
> <http://www.ipamworldwide.com/ipam/isc-dhcpv4-options.html>, which helps.  Is there a cross-reference like this in the isc 
> dhcpd docs somewhere?
> Enclosed is my updated, sanitized dhcpd.conf file with your suggested alterations and a few more of my own.
> Thank you thus far for your time!
> --jason
> On Wed, Jul 29, 2020 at 11:51 AM Bill Shirley <bill at c3po.polymerindustries.biz <mailto:bill at c3po.polymerindustries.biz>> wrote:
>     So, the DISCOVER is not matching any of your classes. Define another pool to issue
>     leases from that doesn't match any class:
>          pool {
>             deny members of "RegionX-RGMGMT-CPE-MODELx";
>             deny members of "RegionX-BOOT-CPE-MODELx";
>             deny members of "RegionX-INET";
>             deny dynamic bootp clients;
>             authoritative;
>             range 192.168.xxx.2 192.168.xxx.15;
>         }
>     This should issue a lease and trigger your 'on commit' log statement.
>     Bill
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