Hi Mike,
Can you just simplify 1-3 below by saying implementations MUST NOT use literal link-local addresses in URI values?
Everything else is ok, right?
Randy
On May 10, 2012, at 10:59 AM, Michael Sweet wrote:
> All,
>> Another issue that has come to light recently is the use of link-local addresses by printers that haven't gotten an IP address from a DHCP server.
>> To summarize the issue: RFC 3986 does not address how to represent link-local addresses in URIs. Two separate (and incompatible) methods have been proposed for IPv6 addresses:
>>http://tools.ietf.org/id/draft-fenner-literal-zone-02.txt (expired)
>http://tools.ietf.org/html/draft-carpenter-6man-uri-zoneid-01>> However, even if one of these methods is eventually adopted it is still impossible for a Printer to advertise the correct URI with a link-local address because zoneid strings are system-specific - they are basically the name of the network interface on the client.
>> What I'd like to do in IPP Everywhere is:
>> 1. Add rationale of not using link-local numeric addresses in printer-uri-supported and other URI values: Link-local numeric addresses cannot be represented by the Printer because the zone identifier is specific to the Client and not the Printer.
>> 2. Add normative requirement: Printers MUST NOT transfer/provide URI values using link-local addresses, SHOULD transfer/provide URIs values using the Host supplied in the Client HTTP request, SHOULD transfer/provide URI values using fully qualified domain names (FQDNs) in preference to numeric addresses, and SHOULD NOT transfer/provide URI values using numeric addresses obtained via DHCP or other auto-configuration protocols. Printers MAY advertise multiple printer-uri-supported values to cover all of the configured FQDNs and non-link-local numeric addresses.
>> 3. Add implementation discussion where the printer can tailor the addresses reported to the Host: value supplied in the client HTTP request; printer-icons, printer-supply-info-uri, printer-more-info are not as flexible as printer-uri-supported, so using the value supplied in the Host HTTP request header is important.
>> 4. Add security considerations text talking about DNS rebinding attacks - Printers SHOULD NOT allow requests with unknown or invalid Host values, including "localhost".
>> 5. Add security considerations text referencing security consideration in current mDNS draft.
>> Thoughts?
>> __________________________________________________
> Michael Sweet, Senior Printing System Engineer, PWG Chair
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