how to set ipv6 next hope

Yogi asked:

I have a tunneling tool that will encap an ipv4 packet in ipv6 packet. However I am not able to configure route to ipv6 next-hop

My next-hop is 2003::1:70:16:234, which is reachable

machine1:/tmp# ping6 2003::1:70:16:234
PING 2003::1:70:16:234(2003::1:70:16:234) 56 data bytes
64 bytes from 2003::1:70:16:234: icmp_seq=1 ttl=64 time=4.29 ms
64 bytes from 2003::1:70:16:234: icmp_seq=2 ttl=64 time=1.73 ms
64 bytes from 2003::1:70:16:234: icmp_seq=3 ttl=64 time=1.75 ms

--- 2003::1:70:16:234 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 1.731/2.590/4.290/1.203 ms

As I try to add route so as to route ipv4 packet destined to through next hop/gw as 2003::1:70:16:234/64, it fails

machine1:/tmp#  route add -net gw 2003::1:70:16:234/64
2003::1:70:16:234/64: **Unknown host  <<<<<<<<<---- ERROR**

However when tried to set next hop as an IPv4 address, route add is successful.

machine1:/tmp#  route add -net gw
machine1:/tmp#  route del -net gw

Any input on what’s so fundamentally wrong in my route command ?

My answer:

What’s fundamentally wrong here is that IPv4 and IPv6 are completely different protocols. You can’t route IPv4 traffic to IPv6 addresses.

I suspect you are trying to tunnel IPv4 traffic somewhere, but since you’ve given no details about that, it’s impossible to say anything further.

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