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<div style="color: rgb(0, 0, 0);"><font face="Calibri">Hello</font></div>
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<div><font face="Calibri">I have the following settings in my dnsmasq.conf, for dnsmasq running on Raspbian/raspberry pi, who has a static ipv6 address of bbbb::1</font></div>
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<div style="color: rgb(0, 0, 0);"><font face="Courier">#dnsmasq.conf on raspberry pi</font></div>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">interface=wlan0</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"><br>
</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">domain=mydomain</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">dhcp-fqdn</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">enable-ra</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">dhcp-option=option6:dns-server,[bbbb::1]</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">dhcp-range=bbbb::,ra-names,1h</font></p>
<p style="margin: 0px; line-height: normal; min-height: 13px;"><font face="Courier"><br>
</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">server=8.8.8.8</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">dhcp-range=192.168.222.50,192.168.222.150,12h</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">dhcp-authoritative</font></p>
<p style="margin: 0px; line-height: normal; min-height: 13px;"><font face="Courier"><br>
</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">#disable DNS</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">port=0</font></p>
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</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">no-resolv</font></p>
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<p style="margin: 0px; line-height: normal;">Here is the ifconfig of the pi:</p>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">wlan0 Link encap:Ethernet HWaddr 74:da:38:42:58:85 </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> inet addr:192.168.222.1 Bcast:192.168.222.255 Mask:255.255.255.0</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> inet6 addr: fe80::76da:38ff:fe42:5885/64 Scope:Link</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> inet6 addr: bbbb::1/64 Scope:Global</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> RX packets:72471 errors:0 dropped:6750 overruns:0 frame:0</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> TX packets:21562 errors:0 dropped:25 overruns:0 carrier:0</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> collisions:0 txqueuelen:1000 </font></p>
<p style="margin: 0px; line-height: normal;"></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"> RX bytes:5101364 (4.8 MiB) TX bytes:4199484 (4.0 MiB)</font></p>
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<div style="font-family: Calibri, sans-serif; font-size: 14px; color: rgb(0, 0, 0);">
I can see the following traffic on the interface wlan0 on the pi, when I execute ‘ping6 bbbb::1’ on the macintosh:</div>
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<p style="margin: 0px; line-height: normal;"><font face="Courier"><b>pi@raspberrypi</b>
<b>~/ndppd-master $</b> sudo tcpdump -i wlan0 icmp6</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">tcpdump: verbose output suppressed, use -v or -vv for full protocol decode</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">listening on wlan0, link-type EN10MB (Ethernet), capture size 65535 bytes</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:38.523668 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:38.529666 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 52, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:39.529612 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 53, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:39.529984 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:40.523668 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:40.539558 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 54, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:41.523674 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:41.531033 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 55, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:42.530378 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 56, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:42.530836 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:43.523661 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:43.530315 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 57, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:44.523668 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:44.529358 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 58, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:45.529469 IP6 bbbb::f65c:89ff:fe89:af6b > bbbb::1: ICMP6, echo request, seq 59, length 16</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:39:45.529828 IP6 bbbb::1 > ff02::1:ff89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Calibri"><br>
</font></p>
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<p style="margin: 0px; line-height: normal;"><font face="Calibri">It appears that my pi is soliciting a multicast address belonging to the mac (ff02::1:ff89:af6b) for the address that dnsmasq assigned to the mac (</font><span style="font-family: Calibri;">bbbb::f65c:89ff:fe89:af6b)
but that the mac does not reply with a neighbor advertisement.</span></p>
<p style="margin: 0px; line-height: normal;"><span style="font-family: Calibri;"><br>
</span></p>
<p style="margin: 0px; line-height: normal;">The neighbor table on the mac looks like this:</p>
<p style="margin: 0px; line-height: normal;"><font face="Calibri"><br>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">Neighbor Linklayer Address Netif Expire St Flgs Prbs</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">bbbb::8a:ae86:b5aa:d727 f4:5c:89:89:af:6b en0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">bbbb::f65c:89ff:fe89:af6b f4:5c:89:89:af:6b en0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::1%lo0 (incomplete) lo0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::250:b6ff:fec9:79f7%en5 0:50:b6:c9:79:f7 en5 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::76da:38ff:fe42:5885%en0 74:da:38:42:58:85 en0 34s R R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::f65c:89ff:fe89:af6b%en0 f4:5c:89:89:af:6b en0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::250:b6ff:fec9:79f7%vlan0 0:50:b6:c9:79:f7 vlan0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::9c75:74ff:fea1:861a%awdl0 9e:75:74:a1:86:1a awdl0 permanent R </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::21b:17ff:fe00:130%vlan1 0:1b:17:0:1:30 vlan1 23h41m35s S R </font></p>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::250:b6ff:fec9:79f7%vlan1 0:50:b6:c9:79:f7 vlan1 permanent R </font></p>
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</font></p>
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<p style="margin: 0px; line-height: normal;"><font face="Calibri">Until the neighbor table is cleared, the mac will never send a neighbor advertisement to the raspberry pi, and thus, the raspberry pi never responds to the ICMP6 request:</font></p>
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</font></p>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">MACINTOSH_EL_CAPITAN$ sudo ndp -cn</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">Password: </font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::76da:38ff:fe42:5885%en0 (fe80::76da:38ff:fe42:5885%en0) deleted</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">fe80::21b:17ff:fe00:130%vlan1 (fe80::21b:17ff:fe00:130%vlan1) deleted</font></p>
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<div>Why is the presence of these two neighbors in the table preventing my macintosh from notifying DNSMASQ on my pi that my mac has the bbbb address that DNSMASQ assigned to it?</div>
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<div>Is the fact that en0 has an identical link-local address to the link-local on wlan0 that would be used for neighbor solicitation/advertisement a problem? (see tcpdump on wlan0 when the neighbor table is cleared on the mac):</div>
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</font></div>
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<p style="margin: 0px; line-height: normal;"><font face="Courier">00:50:20.803643 IP6 fe80::76da:38ff:fe42:5885 > bbbb::f65c:89ff:fe89:af6b: ICMP6, neighbor solicitation, who has bbbb::f65c:89ff:fe89:af6b, length 32</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier">00:50:20.808954 IP6 fe80::f65c:89ff:fe89:af6b > fe80::76da:38ff:fe42:5885: ICMP6, neighbor advertisement, tgt is bbbb::f65c:89ff:fe89:af6b, length 24</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"><br>
</font></p>
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<p style="margin: 0px; line-height: normal;"><font face="Calibri">Above, we see that the pi (fe80::76da:38ff:fe42:5885) solicits the address it gave to the mac on the same link-local neighbor entry deleted off of en0 (fe80::f65c:89ff:fe89:af6b)</font></p>
<p style="margin: 0px; line-height: normal;"><font face="Courier"><br>
</font></p>
<p style="margin: 0px; line-height: normal;">What is dnsmasq doing? Why does it solicit the address that it handed out to my mac? What is it trying to do by soliciting an address that it handed out itself? NUD? Is there a way to disable this solicitation in
dnsmasq? I have noticed that I do not have this problem with radvd — but I would much rather use dnsmasq, as I intend to add DNS services in the future.</p>
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<p style="margin: 0px; line-height: normal;">Best Regards,</p>
<p style="margin: 0px; line-height: normal;">John</p>
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