Are you specifying both the listen_address and listen_interface, or just one of the two?
Send, an example of the following 3 lines. Here is what I have on my 2.1.16 cluster that uses ipv6: listen_address: hhhh:hhhh:hhh:hhhh:h:hhhh:hhh:h # listen_interface: eth0 # listen_interface_prefer_ipv6: false Also, looking at my config, I can confirm that it is uneccessary or wrong to escape the ipv6 address with \ as I suggested before. -Razi On 4/12/17, 4:05 PM, "Martijn Pieters" <mjpiet...@fb.com> wrote: From: "Khaja, Raziuddin (NIH/NLM/NCBI) [C]" <raziuddin.kh...@nih.gov> > Maybe you have to escape the IPV6 addresses in the cassandra.yaml in the same way. > I think it’s worth a try. Nope, no luck. You get an error instead: ERROR [main] 2017-04-12 20:03:46,899 CassandraDaemon.java:752 - Exception encountered during startup: Unknown listen_address 'hhhh\:hhhh\:hhhh\:hhhh\:hhhh\:h\:hh\:h' (actual address digits replaced with h characters). Martijn