On Mon, Jun 11, 2018 at 5:11 AM Shawn Landden shawn@git.icu wrote:

such as those made with Hurricane Electric for ipv6 connectivity

This is because there is no MAC address. They can be made to work if the -G option is used, and set correctly like

iftop -G 2001:470:d:238::/64 -i he-ipv6

to reproduce:

my /etc/network/interfaces iface he-ipv6 inet6 v4tunnel address 2001:470:c:238::2 netmask 64 #LA 0.5ms endpoint 66.220.18.42 local 198.46.198.198 ttl 255 gateway 2001:470:c:238::1 up ip addr add 2001:470:d:238::1 dev he-ipv6

iftop -i he-ipv6 (nothing shows)

reported to debian here https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=901283 it works with tcpdump/libpcap