[aklug] IPv6 Local Link emergency access trick

Since IPv6 Local Link addresses are typically based off of the mac
address of network interfaces you can use a few online calculators to
determine what the IPv6 local link address would be for most systems
running an IPv6 aware operating system with it turned on.

Calculator: http://silmor.de/ipaddrcalc.html#ip6

What came up today was a Linux machine that uses DHCP went offline in
IPv4 land due to an out of space problem.. a very stupid problem to
have. The DHCP client couldn't write a lease to disk so it bailed and
committed suicide. Remote hands were unavailable to help resolve this
issue. Thankfully I had access to other machines on the same Ethernet
segment.

I had the MAC address of the machine I needed to bust in to in my
syslog on my DHCP server.. one quick calculation later and the
following SSH command worked like a champ.

  ssh -6 microadmin@fe80::218:8BFF:FE80:F243%eth0

To quote popular hacker culture.. "I'm in".

Just a quick trick I landed on today.. others have surely done this
before in similar circumstances.

Also.. more proof that static IPs > DHCP static allocations.

- Shane
---------
To unsubscribe, send email to <aklug-request@aklug.org>
with 'unsubscribe' in the message body.
Received on Wed Jul 25 10:21:50 2012