I just got 50 Mbps symmetric fiber from AT&T and it includes a /56 of IPv6 addresses, replacing a much slower ADSL line. I never tried to get IPv6 working on the old connection. I'm using CentOS 7 as a gateway and it's worked great for several versions for IPv4. I'm not seeing any IPv6 default route on the WAN interface. I suspect I'm not getting route announcements. I think I have all the IPv6 variables in ifcfg-em2 set right. But I do notice that the accept_ra file in proc for that interface has value 1, not 2. Changing it to 2 doesn't change anything, though. No route appears. While I wait for an answer to my trouble ticket, is there some way to verify that I'm not receiving any RA packets? Is there a way to force a solicitation for one? Is there a tcpdump invocation I can use to watch for them? Are there log messages that will tell me when an RA has been seen and added to the routing table or ignored?