Why I got error message "Cannot assign requested address"? Tested on Linux Redhat 8.0, Kernel 2.4.20. [root@MN sysconfig]# ifconfig eth1 | grep inet6 inet6 addr: 3ffe:b80:1e99:2::2/64 Scope:Global inet6 addr: fe80::2e0:29ff:fe79:ff5/10 Scope:Link [root@MN sysconfig]# ping6 -I eth1 fe80::2e0:29ff:fe79:ff5 ping: bind icmp socket: Cannot assign requested address [root@MN sysconfig]# ping6 3ffe:b80:1e99:2::2 connect: Cannot assign requested address [root@MN sysconfig]# ping6 -I eth1 3ffe:b80:1e99:2::2 connect: Cannot assign requested address Thank you for reply - Warodom Werapun