On Thu, 10 Dec 2015 16:00, m.roth at ... wrote: > We've started having a problem with a CentOS 7 server. It looses its IPv6 > address, if I understand this issue correctly. We can get in, if we do ssh > -4, though. > > In the logs, I'm seeing this about twice an hour: > <warn> (pid 98466) unhandled DHCP event for interface ens3f0 > > Now, in googling, I get very few hits putting quotes around "unhanded dhcp > exception" - in fact, the only one I found that seemed to talk about it > was from someone's slackware box, where there was some sort of > configuration, perhaps similar to ifcfg-<if>, and they were telling that > person to remove it, because it conflicted with what Networkmanager was > trying to do, leaving it in a confused state. > > Any thoughts? > > mark My first thought upon reading this was: Well, let's block / drop the irritating packets via firewall / iptables. Is the source of these packets allowed to contact your box at all? - No : then block it fully, ipv4 and ipv6 - Yes: block all dhcpv4 / dhcpv6 / radv traffic to and from this source. or even more aggressive: first block this box, second only open the minimum required ports to that box. IMHO, Networkmanager(and its underlaying helpers) should be much more carefull in handling Router / DHCP stuff. It's biggest niggle for me is a missing white- and black-list for (dis-)allowed routers / dhcp-servers. Is this the "Right(tm)" thing to do? Dunno, but that would be my gut-telling. - Yamaban