message: Recommend using net.ipv6.ip_nonlocal_bind on kernels 4.3+
  From Linux kernel 4.3+ there's now the option to set the sysctl `net.ipv6.ip_nonlocal_bind=1`, which makes preloading the freebindfree so obsolete
diff: @@ -319,7 +319,8 @@ ircService:
  # connected user. If not specified, all users will connect from the same
  # (default) address. This may require additional OS-specific work to allow
  # for the node process to bind to multiple different source addresses
  - # e.g IP_FREEBIND on Linux, which requires an LD_PRELOAD with the library
  + # Linux kernels 4.3+ support sysctl net.ipv6.ip_nonlocal_bind=1
  + # Older kernels will need IP_FREEBIND, which requires an LD_PRELOAD with the library
  # https://github.com/matrix-org/freebindfree as Node does not expose setsockopt.
  # prefix: "2001:0db8:85a3::" # modify appropriately
  #
  