ipv6 route add with next hop fails

PieterV

3/19/23, 8:57 AM

I'm trying to add an ipv6 route on machine B to subnet behind next hop A:

2:2:2::2/64 +---+ 192:168:2::1/64      192:168:2::10/64 +---+
       -----| A |---------------------------------------| B |
            +---+                                       +---+

The next hop (192:168:2::1) is reachable (ping succeeds), yet I cannot add it as a next hop in an ipv6 route:

(B):~ > sudo ip -6 route add 2:2:2::/64 via 192:168:2::1
RTNETLINK answers: Invalid argument

Is it possible to get more details about which argument in the ip route add-command is invalid and why? How can I add a route for an ipv6 subnet that is not locally available?

These are the interfaces on machine B:

(ANDEVVM22):~ > ip -6 addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436
    inet6 ::1/128 scope host
        valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
    inet6 3000::c066:def9/64 scope global
        valid_lft forever preferred_lft forever
    inet6 fe80::90af:efff:fe88:2e1b/64 scope link
        valid_lft forever preferred_lft forever
3: eth100: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
    inet6 fe80::102e:2eff:fe41:4887/64 scope link
        valid_lft forever preferred_lft forever
4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 500
    inet6 192:168:1::10/64 scope global
        valid_lft forever preferred_lft forever
5: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 500
    inet6 192:168:2::10/64 scope global
        valid_lft forever preferred_lft forever

104

0 + 0

linux

route

ipv6

John Mahowald

3/20/23, 8:52 PM

Any particular reason you are playing in unallocated bogon space? Generating ULAs, or getting a prefix from an ISP, or even the documentation prefix, would not conflict with the internet.

PieterV

3/22/23, 7:56 AM

This is only used in a test setup, disconnected from the internet. So I assume it doesn't really matter which exact addresses I use?

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: ipv6 route add with next hop fails

TH: การเพิ่มเส้นทาง ipv6 ด้วยการกระโดดครั้งต่อไปล้มเหลว

RO: Adăugarea rutei ipv6 cu următorul hop eșuează

RU: Ошибка добавления маршрута ipv6 со следующим переходом

VI: thêm tuyến ipv6 với hop tiếp theo không thành công

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