<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Feb 13, 2019, at 6:12 PM, Jack Haverty <<a href="mailto:jack@3kitty.org" class="">jack@3kitty.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">…<br class=""><br class="">E.G., the "Multi-homed Host" problem - namely how do you deal with a<br class="">user computer attached to more than one network.</div></div></blockquote><div><br class=""></div>See below. Unsurprisingly, it involves a router inside the end “host”.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div class=""> Does it have two IP<br class="">addresses? </div></div></blockquote><div><br class=""></div><div>Yes, and more for the internal virtual router.</div><br class=""><blockquote type="cite" class=""><div class=""><div class="">Can it effectively use both network ports at the same time? <br class=""></div></div></blockquote><div><br class=""></div>Yes, with “policy routing”.</div><div><br class=""><blockquote type="cite" class=""><div class=""><div class="">Can it be constrained to not act as a gateway?</div></div></blockquote><div><br class=""></div>Yes.<br class=""><br class=""><blockquote type="cite" class=""><div class=""><div class="">...<br class=""><br class="">I haven't been involved for a while, but I wonder if those outstanding<br class="">problems have been solved, perhaps in IPV6.</div></div></blockquote><div><br class=""></div>We experienced this problem in the mid 90s when trying to deploy a somewhat unreliable prototype “gigabit LAN” for operational use. We wanted division-wide participation, but not to interfere with use if (when) the links failed. That included avoiding renumbering impact on long-lived TCP connections (notably telnet logins), NTP (which we couldn’t restart on new addresses without affecting running programs using disk-based files), etc.</div><div><br class=""></div><div>Our solution is documented here, and became part of the basis of our understanding of the nuances of overlay networks in the X-Bone project:<br class=""><br class=""></div><div><span class="tp_pub_author_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;">Touch, J; Faber, T</span><span style="caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);" class="">: </span><span class="tp_pub_title_simple" style="box-sizing: inherit; font-weight: bold; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;"><a class="tp_title_link" style="box-sizing: inherit; -webkit-text-decoration-skip: objects; color: rgb(34, 34, 34); -webkit-box-shadow: rgb(15, 15, 15) 0px -1px 0px inset; box-shadow: rgb(15, 15, 15) 0px -1px 0px inset; transition: color 80ms ease-in, box-shadow 130ms ease-in-out, -webkit-box-shadow 130ms ease-in-out; cursor: pointer;">Dynamic Host Routing for Production Use of Developmental Networks</a></span><span style="caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);" class="">. </span><span class="tp_pub_additional_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;">In: <span class="tp_pub_additional_booktitle" style="box-sizing: inherit;">ICNP, </span><span class="tp_pub_additional_pages" style="box-sizing: inherit;">pp. 285-292, </span><span class="tp_pub_additional_publisher" style="box-sizing: inherit;">IEEE, </span><span class="tp_pub_additional_year" style="box-sizing: inherit;">1997</span>.</span></div><div><span class="tp_pub_additional_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;"><br class=""></span></div><div><span class="tp_pub_additional_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;">Joe</span></div><div><span class="tp_pub_additional_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;"><br class=""></span></div><div><span class="tp_pub_additional_simple" style="box-sizing: inherit; caret-color: rgb(51, 51, 51); color: rgb(51, 51, 51); font-family: "Libre Franklin", "Helvetica Neue", helvetica, arial, sans-serif; font-size: 16px;"><br class=""></span></div></body></html>