Why am I unable to ping the same interface after configuring an IPv6 address

interface ipv6 ping

6,345

The IPv6 address is showing as tentative because duplicate address detection can't be completed. And the reason that can't happen is because you have no physical Ethernet connection (the link shows NO-CARRIER).

To resolve the issue, connect your Ethernet cable.

6,345

JoeChris

i know how solve a problem.

Updated on September 18, 2022

Comments

JoeChris over 1 year
I setup IPv6 in my Ubuntu 12.04 on eth0 using command
```
ifconfig eth0 inet6 add 2001:db8:fedc:cdef::1/64
```
but when i try to ping eth0 itself using
```
ping6 2001:db8:fedc:cdef::1
```
it always gives
```
PING 2001:db8:fedc:cdef:0:0:0:1(2001:db8:fedc:cdef::1)  56 data bytes
 From ::1 icmp_seq=1 Destination unreachable: Address unreachable
 From ::1 icmp_seq=2 Destination unreachable: Address unreachable
 From ::1 icmp_seq=3 Destination unreachable: Address unreachable
```
I think that it automatically is pinging from ::1 to `2001:db8:fedc:cdef::1

Command
```
ip addr show dev eth0
```
it gives
```
2: eth0:<NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
link/ether 00:1b:38:a1:a2:50 brd ff:ff:ff:ff:ff:ff
inet6 2001:db8:fedc:cdef::1/64 scope global tentative 
   valid_lft forever preferred_lft forever
```
Command
```
ip -6 route
```
it gives
```
2001:db8:fedc:cdef::/64 dev eth0  proto kernel  metric 256 
fe80::/64 dev eth0  proto kernel  metric 256 
```
Command
```
ip6tables -L
```
it gives
```
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination   
```
Command
```
ip6tables -F
it gives nothing.
```
Please help how to solve this.
this may have clue for someone

command
```
ip -6 route get 2001:db8:fedc:cdef::1
```
gives
```
2001:db8:fedc:cdef::1 from :: via 2001:db8:fedc:cdef::1 dev eth0  src ::1  metric 0 
cache 
```
why it has src ::1 ?
- Reza Zamani about 11 years
  
  I cannot reproduce this. My guess would be that your eth0 interface is down. Please update your question with the output of ip addr show dev eth0 and maybe ip -6 route.
- Jeremy Visser about 11 years
  
  Also check your ip6tables (run ip6tables -L). You may need to run ip6tables -F.
- JoeChris about 11 years
  
  @celada My eth0 interface is not down. i updated my question with required content.
- JoeChris about 11 years
  
  @Steve-o please how to solve this.
- Steve-o about 11 years
  
  plug in a cable with a carrier signal.
- JoeChris about 11 years
  
  @Steve-o as i m trying to ping the same interface so i unable to understand what is role of cable here. To be more clear i have another ubuntu 12.04 installed which is doing the same for me very well even it also has no-carrier
- JoeChris about 11 years
  
  You are right. IPv6 address does work until you plug ethernet cable. Thanks to alll for reply.
- Eliah Kagan over 6 years
  
  By the way, the same thing will happen with IPv4. You can ping localhost but you cannot ping the machine's IP on the interface when the interface is down or disconnected.
Jeremy Visser about 11 years

This answer is unhelpful and not relevant to the question. Perhaps the O.P. was using the documentation prefix intentionally to make it suitable for posting on the internet? Give the benefit of the doubt here.