I am trying to ssh with Mac OS X (10.10.1 Yosemite) terminal using ipv6. If I use command like

ssh username@ipv6_address

It's not working and I am getting error "No Route to Host". But If I use command like (with %en0)

ssh username@ipv6_address%en0

It's working and I am able to SSH with ipv6 address..

Can you please guide me what's the reason of not working without %en0?


  • Which IPv6 addresses are you using. Having to specify the interface is only necessary when using link-local addresses (those starting with fe80:). Those are not routable and not very convenient to use. You'll want to get routable IPv6 addresses (from an ISP, a tunnel provider or ULA) when using IPv6. Nov 20, 2014 at 6:53
  • @SanderSteffann Yes, It's starting with fe80. Means to connect with local need to specify interface?
    – Temp
    Nov 20, 2014 at 7:00
  • Yes. I'll put this into an answer Nov 20, 2014 at 10:39
  • 1
    superuser.com/q/99746/144961 Nov 20, 2014 at 17:50

1 Answer 1


When you want to connect to an unroutable address like link-local you need to specify the interface. This is because for unroutable addresses your system can't determine the outgoing interface by looking at the routing table.

Unroutable destinations include link-local addresses (fe80::) and link-local multicast (ff02::) and more.

  • Thanks for the reply. For routable ipv6 address, I can get from ISP, correct? or need any changes in network configuration?
    – Temp
    Nov 20, 2014 at 12:15
  • From your ISP, or for internal use (not to connect to the internet) you can generate your own ULA addresses. Nov 20, 2014 at 18:49
  • Thank you for this @SanderSteffann! Do you happen to have any idea how to specify a link-local IPv6 destination in Safari or Chrome on MacOS? With routable inet6 addresses, putting the address in square brackets works: http://[fed0:ad::2]/login. I can't figure out how to give either browser the interface information though. Putting it in the brackets not surprisingly makes it do a search for what I've entered, since it's no longer a valid inet6 address.
    – Avram
    Dec 8, 2023 at 17:43

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