Linux Networking Cookbook

15.4. Using SSH with IPv6

Problem

Can you do remote administration with SSH using IPv6?

Solution

Of course you can, like this:

	$ ssh fe80::214:2aff:fe54:67d6%eth0
	carla@fe80::214:2aff:fe54:67d6%eth0's password:
	Linux uberpc 2.6.20-15-generic #2 SMP Sun Apr 15 07:36:31 UTC 2007 i686
	Last login: Wed Jun 6 18:51:46 2007 from xena.alrac.net
	carla@uberpc:~$

Note that for Link Local addresses you must specify your network interface and preface it with the percent sign. You can log in as a different user this way:

	$ ssh user@fe80::214:2aff:fe54:67d6%eth0

If you're using unicast addresses, you don't need to specify the interface:

	$ ssh user@FC01::1

Copying files with scp is a pain because you have to enclose the address in brackets and then escape the brackets:

	$ scp filename.txt \[FC01::2\]:
	carla@fc01::2's password:
	filename.txt

Discussion

This isn't all that useful in the real world because it's likely you'll be relying on DNS more than IPv6 addresses. But it is helpful for testing and troubleshooting.

If you have access controls set up on your SSH server, you may need to change some options to permit logins via IPv6:

AddressFamily

The default is any. You may also use inet for IPv4, or inet6.

ListenAddress

The default is any. If you are restricting access by IP addresses, you'll need to add the local IPv6 address.

See Also

• man 1 ssh

• man 5 sshd_config

• man 1 scp