problems configuring option 120

Glenn Satchell Glenn.Satchell at uniq.com.au
Wed Dec 9 13:45:12 UTC 2009


Hi Rebeca

Well it looks like dhcp server is handing out the right info, 0A0103C9
is hex, and decoded it becomes 0A = 10, 01 = 1, 03 = 3, c9 = 201. Now
it's a matter of reading the documentation for your sip client to see
what it is expecting, and making sure all those options are supplied in
the right format. There may be other options that also need to be set
before the client will be satisfied. We can't tell that without the
client documentation.

Is the network routing set up correctly to allow the client with a
192.168.xx.xx address to send packets to 10.1.3.201 and back again?

regards,
-glenn

>Subject: RE: problems configuring option 120
>Date: Wed, 9 Dec 2009 14:06:08 +0100
>From: "Martínez García, Rebeca" <remartinez at indra.es>
>
> 
> Hi all,
> 
> I have progressed in the option 120 configuration. My dhcpd.conf now is like 
that:
> 
> 
> option sip-servers code 120 = { integer 8, ip-address };
> 
> subnet	192.168.xx.xx netmask 255.255.255.0 {
> 
> 	option routers 192.168.xx.xx;
> 	option subnet-mask 255.255.255.0;
> 	option broadcast-address 192.168.xx.xx;	
> 	option domain-name "xxxxxxxxxx";
> 	option domain-name-servers 192.168.xx.xx;
> 	option sip-servers 1 10.1.3.201;
> 	default-lease-time 3600;
> 	max-lease-time 86400;
> 	ddns-update-style none;
> 	authoritative;
> 	log-facility local7;
> 
> 	host Alice {
> 		hardware ethernet xx:xx:xx:xx:xx:xx;
> 		fixed-address 192.168.xx.xx;
> 	}
> 	host Becky {
> 		hardware ethernet xx:xx:xx:xx:xx:xy;
> 		fixed-address 192.168.xx.xx;
> 	}
> }
> 
> So, restarting the dhcp server now is successful but when the client asks for 
the 120 option information, my dhcp server answers like this:
> 
> Option: (t=120, l=5) SIP Servers
>    Option: (120) SIP Servers
>    length: 5
>    Value: 0A0103C9 
> 
> However, the client tries again to ask for the information with another 
DHCPINFORM although it is in the "Value" field. 
> Where is the problem, in my dhcp server configuration or in the client?
> 
> Thanks in advance,
> Rebeca Martinez
> 
> -----Mensaje original-----
> De: dhcp-users-bounces at lists.isc.org en nombre de David W. Hankins
> Enviado el: lun 07/12/2009 21:28
> Para: Users of ISC DHCP
> Asunto: Re: problems configuring option 120
>  
> On Mon, Dec 07, 2009 at 11:13:44AM +0100, "Martínez García, Rebeca" wrote:
> > 	option sip-servers code 120 = ip-address;
> 
> The indentation tells me you put this in your subnet {} clause or
> similar.  This is a declaration of the option's format, it has to be
> globally scoped as the warning tries to say;
> 
> > /etc/dhcp3/dhcpd.conf line 14: option definitions may not be scoped.
> >       option sip-servers code 
> >                ^
> 
> However, the SIP-Servers option declared on code 120 (RFC 3361) shows
> a "conditional format" key on the first octet, so the syntax you have
> declared would not be compatible with RFC 3361.
> 
> To make it compatible you'll need an unsigned 8 bit integer ahead of
> the IP address array, and then declare a 1 value for the encoding byte
> to use the IP-address format (0 is FQDN).
> 
> These conditional formats are hard to implement...
> 
> -- 
> David W. Hankins	BIND 10 needs more DHCP voices.
> Software Engineer		There just aren't enough in our heads.
> Internet Systems Consortium, Inc.		http://bind10.isc.org/




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