<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 31, 2016, at 12:18 PM, Gary E. Miller <<a href="mailto:gem@rellim.com" class="">gem@rellim.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">RFC 826 defines ARP. It makes no mention of how long the timeout<br class="">should be.<br class=""><br class="">Cisco uses 4 hours.<br class=""><br class="">I can not find the info on OS X.<br class=""></div></div></blockquote><br class=""></div><div>From `man 4 arp` on OS X (El Capitan):</div><div><br class=""></div><div><div style="margin: 0px; font-size: 13px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">The ARP cache is stored in the system routing table as dynamically-created host routes. The route to a directly-attached Ethernet net</span>work is installed as a ``cloning'' route (one with the RTF_CLONING flag set), causing routes to individual hosts on that network to be created on demand. These routes time out periodically (<b class="">normally 20 minutes after validated</b>; entries are not validated when not in use).</div></div><br class=""><div class="">Is that what you were looking for on OS X?</div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">Frank</div></body></html>