Hi, I think multipath over device routes for ipv6 requires using new nexthop objects. Here is an example:
# ip link add name a type dummy # ip link add name b type dummy # ip link set dev a up # ip link set dev b up # ip -6 route add fc00:0::/32 dev a # ip -6 route add fc00:1::/32 dev b # ip -6 route add fc00:2::/32 nexthop dev a Error: Device only routes can not be added for IPv6 using the multipath API. # ip -6 route add fc00:3::/32 nexthop dev a nexthop dev b Error: Device only routes can not be added for IPv6 using the multipath API. # ip -6 nexthop add id 100 dev a # ip -6 nexthop add id 101 dev b # ip nexthop add id 102 group 100/101 # ip -6 route add fc00:4::/32 nhid 102 # ip -6 route list fc00::/32 dev a metric 1024 pref medium fc00:1::/32 dev b metric 1024 pref medium fc00:4::/32 nhid 102 metric 1024 pref medium nexthop dev a weight 1 nexthop dev b weight 1 fe80::/64 dev a proto kernel metric 256 pref medium fe80::/64 dev b proto kernel metric 256 pref medium # sysctl -w net.ipv4.nexthop_compat_mode=0 net.ipv4.nexthop_compat_mode = 0 # ip -6 route list fc00::/32 dev a metric 1024 pref medium fc00:1::/32 dev b metric 1024 pref medium fc00:4::/32 nhid 102 metric 1024 pref medium fe80::/64 dev a proto kernel metric 256 pref medium fe80::/64 dev b proto kernel metric 256 pref medium # ip nexthop list id 100 dev a scope link id 101 dev b scope link id 102 group 100/101 On Wed, Feb 19, 2025 at 2:20 PM Ondrej Zajicek <santi...@crfreenet.org> wrote: > On Wed, Feb 19, 2025 at 10:39:53AM +0800, Jimmy Lim wrote: > > Hi Maria, > > > > It looks like it doesn't like the configuration of directing IPv6 prefix > > that we receive from gw (we have 3 sessions) to ifname. The multipath is > > working fine for IPv6 after I removed that configuration, and it works > for > > both bird v1 and v2: > > Hi > > Yeah, there was some kernel issue rekated to IPv6 multipath direct > routes. We have some workaround in the code for this case, but likely > only for the recent versions of BIRD. > > -- > Elen sila lumenn' omentielvo > > Ondrej 'Santiago' Zajicek (email: santi...@crfreenet.org) > "To err is human -- to blame it on a computer is even more so." >
