<div dir="ltr">Never mind. Forgot to check the firewall, and need to punch a hole in ip6tables.<div><br></div><div>George</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Dec 15, 2016 at 5:57 PM, George Sheng <span dir="ltr"><<a href="mailto:georgesheng14@gmail.com" target="_blank">georgesheng14@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div>I'm playing with the ISC dhcp 4.3.5 code, on centos 6 and 7 hosts.</div><div><br></div><div>client                           relay or server</div><div> host1 <-- ethernet --> host2</div><div>      vlan20                 vlan20</div><div><br></div><div>I can see the dhclient send out solicit packets from host1, and</div><div>tcpdump on host2 prints out it gets the packets:</div><div><br></div><div>







<p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">tcpdump -i enp3s0.20 udp -vv:</span></p></div><div>







<p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">17:44:23.377713 IP6 (hlim 1, next-header UDP (17) payload length: 71) fe80::211:2fff:fe85:8cf4.<wbr>dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=8cb62a (client-ID hwaddr/time type 1 time 535166114 00112f858cf4) (option-request DNS-server DNS-search-list) (elapsed-time 709) (Client-FQDN) (IA_NA IAID:797281524 T1:3600 T2:5400))</span></p>
<p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">17:44:31.365915 IP6 (hlim 1, next-header UDP (17) payload length: 71) fe80::211:2fff:fe85:8cf4.<wbr>dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=8cb62a (client-ID hwaddr/time type 1 time 535166114 00112f858cf4) (option-request DNS-server DNS-search-list) (elapsed-time 1508) (Client-FQDN) (IA_NA IAID:797281524 T1:3600 T2:5400))</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1"><br></span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">But the dhcrelay never receives any packet on the vlan20 interface:</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1"><br></span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">relay/dhcrelay -6 -d -l enp3s0.20 -u e3s0.10</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">[sudo] password for naiming: </span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Internet Systems Consortium DHCP Relay Agent 4.3.5</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Copyright 2004-2016 Internet Systems Consortium.</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">All rights reserved.</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">For info, please visit <a href="https://www.isc.org/software/dhcp/" target="_blank">https://www.isc.org/software/<wbr>dhcp/</a></span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Bound to *:547</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Listening on Socket/enp3s0.10</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Sending on   Socket/enp3s0.10</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Listening on Socket/enp3s0.20</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">

















</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Sending on   Socket/enp3s0.20</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1"><br></span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">I have debugs inside the socket code trying to see if there is any receiving packet, no.</span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1"><br></span></p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1">Has anyone have experience on this DHCPv6 setup? maybe this is particular to vlan?</span></p><p class="m_-328172346319242843gmail-p1">thanks.</p><span class="HOEnZb"><font color="#888888"><p class="m_-328172346319242843gmail-p1"><br></p><p class="m_-328172346319242843gmail-p1">George</p><p class="m_-328172346319242843gmail-p1"><span class="m_-328172346319242843gmail-s1"><br></span></p></font></span></div></div>
</blockquote></div><br></div>