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<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Yes, I understand your consumer dynamic scenario…In the "old" days, admins would configure a service name (like "printer,<a href="http://apple.com">apple.com</a>") to return multiple IP addresses, and socket API recommendations say you're supposed to walk the list of returned addresses until you successfully connect to one. So there would be a slight delay if you were home and wanted to access imac27.mike.members.icloud.com (unless the home IP address was the first address returned).</div><div><br></div><div>It gets even more complicated if your DNS setup is dual-stack in which case you're returning both A and AAAA records, in which case local resolver policy may force a delay if clients try to resolve IPv6 before IPv4 or vice-versa.</div><div><br></div><div>R.</div><div><br></div><div><div><div>On May 11, 2012, at 10:25 AM, Michael Sweet wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On May 11, 2012, at 9:43 AM, Randy Turner wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Hi Mike,</div><div><br></div><div>Good discussion.</div><div><br></div><div><div>The VPN-name vs. LAN-name situation is normally cleared up by 2-headed DNS, which most companies employ all the time -- that's not a problem we need to solve.</div></div></div></blockquote><div><br></div><div>I agree that N-headed DNS works well for managed, mostly-static infrastructure. However, dynamic consumer services like dyndns and iCloud don't (and can't, as far as I can see) work that way.</div><div><br></div><div>For example, Apple has something called "Back to My Mac" that allows you to access your computers via iCloud, which handles setting up a secure tunnel between the two computers using your iCloud account. Part of this service is a DNS subdomain for your iCloud account, so I can access "imac27.NNNNNN.btmm.members.icloud.com" to get to my iMac at home. However, if I try to use that hostname when I am at home it won't work because the VPN address doesn't route from my home network.</div></div><div><br></div><div>Similarly, I have a DynDNS account setup that allows me to access that same iMac from non-Mac computers. The DynDNS hostname works great outside my home network, but does not work on the home network.</div><div><br></div><div><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>...</div><div>While it may be possible for a device to advertise multiple URIs for both the principal service, and other URIs (identifying different physical servers) for associated resources, I hope this is the exception and not the rule -- in fact, I would say we need a recommendation that says IPP Everywhere deployments SHOULD NOT use disseparate servers -- it makes the overall aggregate "uptime" for the service questionable, and creates potentially complicated policies for defaults if/when these associates resources are (for some reason) not available.</div></div></div></blockquote><div><br></div>I suspect that consumer products will "obey" this limitation, but you can expect enterprise and "prosumer" products will continue to support (re)configuration of the printer to report externally-available resources. I say "continue to" because existing IPP-based printers already support this functionality.</div><div><br></div><div>
<span class="Apple-style-span" style="border-collapse: separate; font-family: Geneva; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Geneva; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Geneva; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Monaco; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>________________________________________________________________________</div><div>Michael Sweet, Senior Printing System Engineer, PWG Chair</div></div></span></div></span></div></span></span>
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