RFC 8910

Ÿnérant ynerant at crans.org
Wed Apr 20 15:26:57 UTC 2022


Thank you. My requests didn't include the option 114 indeed. I tried to
ask it, and the server answers me correctly.

It is now time for me to see how clients deal with this information.

Thank you!

Regards,

-- 
Yohann D'Anello


Le mercredi 20 avril 2022 à 10:57 -0400, perl-list a écrit :
> The server will only send these options if the client asks for them. 
> In the discover or request packets from the client, have a look at
> option 55 (parameter request list).  If that list does not contain
> option 114 or 160 then the server won't send them.  Even if the
> server did send them without being requested, the client would likely
> ignore them not knowing what to do with them.
> 
> ----- Original Message -----
> > From: "Ÿnérant" <ynerant at crans.org>
> > To: "Users of ISC DHCP" <dhcp-users at lists.isc.org>
> > Sent: Wednesday, April 20, 2022 10:04:00 AM
> > Subject: RFC 8910
> 
> > Hello!
> 
> > For my organization, I am using isc-dhcp-server as DHCP server.
> 
> > We want to deploy a captive portal for a new open Wifi to
> > authenticate
> > users. However, we want to do it great, and avoid to do Man-in-the-
> > middle attacks to access the portal. The RFC 8910 let the DHCP
> > server
> > to send an API URI that indicates the presence of a captive portal,
> > and
> > let the clients to detect the presence of a captive portal and the
> > URL
> > that let them to authenticate.
> 
> > However, I think that the RFC is not implemented yet. The RFC
> > replaces
> > the RFC 7710 (which added a captivep-portal-url option) and the RFC
> > 3679, which added a default-url option. The present RFC overwrites
> > this
> > option, number 114.
> 
> > I just added in my configuration the following options:
> 
> > option default-url "https://example.com/api.json"; # 114 from
> > RFC3679
> > option v4-captive-portal "https://example.com/api.json"; # 160 from
> > RFC7710
> 
> > These are recognized by isc-dhcp-server. But when I launch the
> > server
> > and add a client, I don't see any of the two options when I analyse
> > the
> > DHCP packets (with tcpdump or Wireshark for example). Did I make
> > something wrong? Is there something unimplemented?
> 
> > One more question: does someone know how clients react to this DHCP
> > option? Who really cares about this URL? When is the client
> > informed
> > that there is a captive portal, and how is they redirected?
> 
> > Regards,
> 
> > --
> > Yohann D'Anello
> 
> > --
> > ISC funds the development of this software with paid support
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> > Contact us at https://www.isc.org/contact/ for more information.
> 
> > dhcp-users mailing list
> > dhcp-users at lists.isc.org
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