Hi,
I am using iperf version 2.0.5 and I am not able to run the traffic it displays error invalid argument. Please find the below log. ping6 <ipv6 ip> doesnot ping instead I need to give ping6 -I <interface> <ipv6 ip> then it ping. Please find the below log and provide me the immediate solution for the same

Server log:
-----------
[root@localhost ~]# ping6 fe80::225:b5ff:fe00:3f
connect: Invalid argument
[root@localhost ~]# ping6 -I eth0 fe80::225:b5ff:fe00:3f
PING fe80::225:b5ff:fe00:3f(fe80::225:b5ff:fe00:3f) from fe80::225:b5ff:fe00:3f eth0: 56 data bytes
64 bytes from fe80::225:b5ff:fe00:3f: icmp_seq=1 ttl=64 time=0.034 ms
64 bytes from fe80::225:b5ff:fe00:3f: icmp_seq=2 ttl=64 time=0.023 ms
64 bytes from fe80::225:b5ff:fe00:3f: icmp_seq=3 ttl=64 time=0.024 ms
^C
--- fe80::225:b5ff:fe00:3f ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2406ms
rtt min/avg/max/mdev = 0.023/0.027/0.034/0.005 ms
[root@localhost ~]# iperf -s -B fe80::225:b5ff:fe00:3f -V
bind failed: Invalid argument
------------------------------------------------------------
Server listening on TCP port 5001
Binding to local address fe80::225:b5ff:fe00:3f
TCP window size: 85.3 KByte (default)
------------------------------------------------------------


Client log:
------------
[root@localhost ~]# ping6 fe80::225:b5ff:fe00:3f
connect: Invalid argument
[root@localhost ~]# ping6 -I eth0 fe80::225:b5ff:fe00:3f
PING fe80::225:b5ff:fe00:3f(fe80::225:b5ff:fe00:3f) from fe80::225:b5ff:fe00:f eth0: 56 data bytes
64 bytes from fe80::225:b5ff:fe00:3f: icmp_seq=1 ttl=64 time=1.07 ms
64 bytes from fe80::225:b5ff:fe00:3f: icmp_seq=2 ttl=64 time=0.197 ms
^C
--- fe80::225:b5ff:fe00:3f ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1695ms
rtt min/avg/max/mdev = 0.197/0.635/1.073/0.438 ms
[root@localhost ~]# iperf -c fe80::225:b5ff:fe00:3f -i 1 -V
connect failed: Invalid argument
[root@localhost ~]#

This is to be expected, as fe80::/16 is the "link-local" address range, meaning these addresses can exist behind any interface. As such, the address "fe80::225:b5ff:fe00:3f" is actually ambiguous; it may refer to any number of hosts on different local networks.

Pinging (or otherwise attempting to reach) a link-local address is only possible if one also specifies the interface. Otherwise, the IPv6 stack won't know where to look for the address.

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