function avoid_martians6()
  prefix set martians;
  {
    martians = [
      0000::/8{8,128},        # loopback, unspecified, v4-mapped
      0064:ff9b::/96{96,128}, # IPv4-IPv6 Translat. [RFC6052]
      0100::/8{8,128},        # reserved for Discard-Only Address Block [RFC6666]
      0200::/7{7,128},        # Reserved by IETF [RFC4048]
      0400::/6{6,128},        # Reserved by IETF [RFC4291]
      0800::/5{5,128},        # Reserved by IETF [RFC4291]
      1000::/4{4,128},        # Reserved by IETF [RFC4291]
      2001::/32{33,128},      # Teredo prefix [RFC4380]
      2001:0002::/48{48,128}, # Benchmarking [RFC5180]
      2001:0003::/32{32,128}, # Automatic Multicast Tunneling [RFC7450]
      2001:10::/28{28,128},   # Deprecated ORCHID [RFC4843]
      2001:20::/28{28,128},   # ORCHIDv2 [RFC7343]
      2001:db8::/32{32,128},  # NON-ROUTABLE range to be used for  documentation purpose [RFC3849]
      2002::/16{17,128},      # 6to4 prefix [RFC3068]
      3ffe::/16{16,128},      # used for the 6bone but was returned [RFC5156]
      4000::/3{3,128},        # Reserved by IETF [RFC4291]
      5f00::/8{8,128},        # used for the 6bone but was returned [RFC5156]
      6000::/3{3,128},        # Reserved by IETF [RFC4291]
      8000::/3{3,128},        # Reserved by IETF [RFC4291]
      a000::/3{3,128},        # Reserved by IETF [RFC4291]
      c000::/3{3,128},        # Reserved by IETF [RFC4291]
      e000::/4{4,128},        # Reserved by IETF [RFC4291]
      f000::/5{5,128},        # Reserved by IETF [RFC4291]
      f800::/6{6,128},        # Reserved by IETF [RFC4291]
      fc00::/7{7,128},        # Unique Local Unicast [RFC4193]
      fe80::/10{10,128},      # Link Local Unicast [RFC4291]
      fec0::/10{10,128},      # Reserved by IETF [RFC3879]
      ff00::/8{8,128}         # Multicast [RFC4291]
    ];
    if net ~ martians then return true;
    return false;
}

filter somefilter {
    if ! (avoid_martians6()) then reject;
    accept;
}