static clients: how log hostnames and create lease entries?

[Glenn Satchell]

Hi Frantisek

One other possibility is to offer a *really* long regular lease, like 1
or 2 years. It will effectively be the same as a static lease, but will
be a dynamic lease and go through all the dynamic lease things, like
dhcpd.leases, but without worrying about the hassle of reserved leases.

group {
	# 1 year in seconds
	min lease-time 31536000;
	host "host1" { hardware ethernet x:x:x:x:x:x ; }
	host "host2" { hardware ethernet y:y:y:y:y:y ; }
	...
}

or you could do a similar thing with a class and sub-class, note the
leading 1 which means media type ethernet.

class "really-long" {
	match pick-first-value (option dhcp-client-identifier, hardware);
	# 1 year in seconds
	min lease-time 31536000;
}
subclass "really-long" 1:x:x:x:x:x:x;
subclass "really-long" 1:y:y:y:y:y:y;

regards,
-glenn

>Date: Sat, 26 Dec 2009 23:42:14 +0100
>From: Frantisek Hanzlik <franta at hanzlici.cz>
>
>Simon Hobson wrote:
>> Frantisek Hanzlik wrote:
>>
>>> I there some way how, for host declarations with static addresses, do:
>>>
>>> 1) log client hostname (which client sent in DHCPREQUEST or DHCPDISCOVER
>>> as option 12 ) ?
>>>
>>> 2) so that they appear in lease file ?
>>
>> I don't think so.
>>
>> However, if you converted to use reserved leases then the clients get
>> 'real' leases which go through the normal lifecycle, appear in the
>> leases file, and get DNS updates/deletes etc - the only difference from
>> a normal lease being that a reserved lease will never be re-allocated to
>> another client. I think you need version 4 for this functionality, and I
>> don't know how well it's documented. I believe you need to manually add
>> "reserved" as a keyword in an existing lease (or create a new skeleton
>> lease with this) to uset he feature - and of course, that means stopping
>> the server while you edit the leases file.
>
>
>For now I have solved (but not sure when it's optimal) point 1) with
>custom logging defined in global section as this:
>
>----
>on commit {
>   if (static){set isst = "static";} else {set isst = "dynamic";}
>   log (info, concat (
>     "COMMIT IP,", binary-to-ascii (10,8,".",leased-address),
>     ",MAC,", suffix (concat ("0", substring(binary-to-ascii (16, 8, ":", 
hardware), 2, 17)),17),
>     ",hostname,", option host-name,
>     ",host-decl-name,", pick-first-value(host-decl-name, "(none)"),
>     ",dhcp-client-identifier,", 
pick-first-value(binary-to-ascii(16,8,"",option dhcp-client-identifier), 
"(none)"),
>     ",vendor-class-identifier,", pick-first-value(option 
vendor-class-identifier, "(none)"),
>     ",agent.remote,", pick-first-value(option agent.remote-id, "(none)"),
>     ",agent.circuit,", pick-first-value(option agent.circuit-id, "(none)"),
>     ",leasetime,", binary-to-ascii (10,32,"",encode-int (lease-time,32)),
>     ",asstype,", isst
>     )
>   );
>}
>----
>This produces (in addition to usual) log items as:
>
>Dec 26 23:29:56 ns dhcpd: COMMIT 
IP,192.168.1.250,MAC,00:20:ed:72:fb:5f,hostname,q,host-decl-name,janusa,dhcp-cli
ent-identifier,1020ed72fb5f,vendor-class-identifier,MSFT 
5.0,agent.remote,(none),agent.circuit,(none),leasetime,216000,asstype,static
>
>which is quite sufficient for me.
>
>This don't need any additional requirements, but it not solve point 2).
>I have DHCP v4.0 or 4.1 servers (Fedora 10 - Fedora 12 machines), but
>manually edit lease file seems little crazy for me.
>"infinite-is-reserved On" dhcpd.conf statement isn't answer, because
>as far as I understand man page, client itself must request infinite
>lease time - which isn't realistic.
>dhcpd.leases man page in addition to "reserved" mention also "bootp"
>flag, but again without any details.
>
>Then, I still not know, when there is any elegant way how put fixed
>address hosts to dhcpd.leases file. I do not need any dyndns updates etc.
>
>Any advice?
>
>Thanks, Franta Hanzlík
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