<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=iso-2022-jp"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Aptos;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Aptos",sans-serif;
mso-ligatures:standardcontextual;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Aptos",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:11.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#467886" vlink="#96607D" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Dear colleagues, <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have been attempting to test a setup in the lab with DOCSIS CM operating in IPv6 mode only, where the DHCPv6 messages are relayed across the CMTS and the first-hop router (relay address 2600:6ce4:0:3e::1) towards a Kea server running 2.4 code (address 2600:6ce4:0:42::130). <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>At the Kea server level, I ran a packet capture, to observe an interesting behavior – the Solicit messages from the DOCSIS CM are being forwarded back to the relay, embedded within the ICMPv6 message with indication that the destination is unreachable for some reason. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><img width=1515 height=108 style='width:15.7833in;height:1.125in' id="Picture_x0020_1" src="cid:image001.png@01DA955E.D77BCC10"><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The Kea server is running without any issues so it seems that the binding is successful and <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:"Courier New"'>root@server-kea-node1:/home/ace# service isc-kea-dhcp6-server status <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>● isc-kea-dhcp6-server.service - Kea DHCPv6 Service<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Loaded: loaded (/lib/systemd/system/isc-kea-dhcp6-server.service; enabled; vendor preset: enabled)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Active: active (running) since Tue 2024-04-23 15:02:41 UTC; 11min ago<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Docs: man:kea-dhcp6(8)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Main PID: 1551 (kea-dhcp6)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Tasks: 7 (limit: 4550)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> Memory: 3.5M<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> CPU: 119ms<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> CGroup: /system.slice/isc-kea-dhcp6-server.service<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'> └瘢雹─1551 /usr/sbin/kea-dhcp6 -c /etc/kea/kea-dhcp6.conf<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:29 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:29.467 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_CONNECTION_OPENED Opened socket 22 for incoming command connection<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:29 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:29.468 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_READ Received 129 bytes over command socket 22<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:29 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:29.468 INFO [kea-dhcp6.commands/1551.140682475032192] COMMAND_RECEIVED Received command 'statistic-get'<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:29 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:29.468 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_WRITE Sent response of 92 bytes (0 bytes left to send) over command socket 22<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:29 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:29.468 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_CONNECTION_CLOSED Closed socket 22 for existing command connection<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:30 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:30.158 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_CONNECTION_OPENED Opened socket 22 for incoming command connection<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:30 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:30.158 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_READ Received 117 bytes over command socket 22<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:30 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:30.158 INFO [kea-dhcp6.commands/1551.140682475032192] COMMAND_RECEIVED Received command 'statistic-get-all'<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:30 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:30.158 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_WRITE Sent response of 8715 bytes (0 bytes left to send) over command socket 22<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>Apr 23 15:14:30 server-kea-node1 kea-dhcp6[1551]: 2024-04-23 15:14:30.158 DEBUG [kea-dhcp6.commands/1551.140682475032192] COMMAND_SOCKET_CONNECTION_CLOSED Closed socket 22 for existing command connection<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I attach the Kea DHCPv6 config for reference (keav6.json) – the test device should match rpd-10 class, and make its way into 2600:6ce4:0:3e::/64 subnet. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I am drawing blank on what the problem might be in here. I have not seen this behavior before and I am not sure whether it is related with the fact that I have two layers of relays in messages or not<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Marek<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>