string data expressions (was Re: using option 82 to assign a static ip-address)

perl-list perl-list at network1.net
Wed Dec 19 14:54:54 UTC 2012


The problem is that the config isn't human generated. Was trying to avoid maintaining a list of equipment for option 82 purposes and instead just providing a field in which any ASCII text could be entered. But, since there needs to be a distinction still, there will need to be a list of possible equipment that could be generating the option 82 so that we can correlate whether it is ASCII or binary in the packet. We could have the user choose ASCII or binary but they probably wouldn't know what we are talking about. So, in the drop down we will have choices such as Cisco, Juniper, Brocade, Calix, Occam ... I know, for example, that Brocade is binary and that Occam is ASCII. Some vendors use a telco standard (name escapes me at the moment ) for the option 82 , some use their own made up standard. Occam seems to have the most reasonable setup by letting the user define what ASCII text should be returned per port so that they can name them based on something that has specific meaning. Anyways - it is (not) a lot of fun :) 

----- Original Message -----

> From: "Simon Hobson" <dhcp1 at thehobsons.co.uk>
> To: "Users of ISC DHCP" <dhcp-users at lists.isc.org>
> Sent: Wednesday, December 19, 2012 9:35:50 AM
> Subject: Re: string data expressions (was Re: using option 82 to
> assign a static ip-address)

> perl-list wrote:
> > bah - that is what I feared. The problem I have is not knowing what
> > will be received at each site (depends on vendor) and hoping to
> > find a solution that works with all to prevent re-configsevery
> > timesomeone somewhere adds some new equipment, and worse yet,
> > matching things in a multi-vendor environment when you aren't sure
> > what will come from where.

> Sorry, I don't understand what the problem is.

> If you are having to match on <some option> then presumably you have
> some idea what is in the option. In all cases, if you are using
> something like "option blah = <something>" then there's no problem.
> If you expect <something> to look like a string then specify the
> string in quotes :
> option option-82 = "Switch 0 Port 3"
> If you expect it to be "non text" then specify it as a hex string :
> option option-82 = "00:03" # if, for example, the equipment just sent
> two octets with switch and port number

> This will work with all sites, using a common config format. All it
> requires is that you put quotes in your database round text values,
> and not around hex representations.

> If this doesn't cover your problem, then perhaps you'd better expand
> on what your problem is.

> --
> Simon Hobson

> Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
> author Gladys Hobson. Novels - poetry - short stories - ideal as
> Christmas stocking fillers. Some available as e-books.
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