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<p>Not sure whether it's fine to send this there.<br>
<br>
The scenario:<br>
Interface ETH0, has and only has IPv4:192.168.1.2 and IPv6 aaaa::cccc. Now the IPv4 address is down, and the IPv6 address is up. And ranges of 192.168.1.0 and aaaa::/64 are configured. Next start the DHCP server with IPv6(-6), the result is the ETH0 is skipped with no message in the log about this interface. If the IPv4 is up, the ETH0 can be listened.<br>
<br>
After debug, I locate the code in discover.c:<br>
<br>
/* Skip non broadcast interfaces (plus loopback and<br>
point-to-point in case an OS incorrectly marks them<br>
as broadcast). Also skip down interfaces unless we're<br>
trying to get a list of configurable interfaces. */<br>
if (((!(info.flags & IFF_BROADCAST) ||<br>
info.flags & IFF_LOOPBACK ||<br>
info.flags & IFF_POINTOPOINT) && !tmp) ||<br>
(!(info.flags & IFF_UP) &&<br>
state != DISCOVER_UNCONFIGURED))<br>
continue;<br>
<br>
On the surface, the interface can be listened depending on the state of IPv4 address when starting IPv6 DHCP, but it shouldn't. The key point here is the IFF_BROADCAST flag, for ordinary IPv4 address, it's broadcast address valid, but for IPv6, which has not broadcast, but has multicast (IFF_MULTICAST), so i think it would need to differentiate the IPv4 and IPv6 when to check which interface needs to skip.<br>
<br>
Best&Regards<br>
Andy</body></html>