Solved - Re: Figuring out a headless server's zeroconf addr

[Robert Moskowitz]

Kind of.

No zeroconf.  For some reason.  But at least ipv6 local-scope.

Used wireshark to capture dhcp probes to get MAC address.

Converted MAC address into IPv6 local scope address.

ssh ipv6%interface

and I am in!

Now to later do this later to the actual box rather than between two 
notebooks.  But it should work the same!

On 07/21/2014 12:34 PM, Robert Moskowitz wrote:
>
> On 07/21/2014 11:25 AM, Tim wrote:
>> On Mon, 2014-07-21 at 10:55 -0400, Robert Moskowitz wrote:
>>> I have a headless system that I cannot connect to.  So I was thinking
>>> to put a direct connection to it and my notebook.  Both ethernets
>>> would use the zeroconf (169.254.0.0/16) addresses.  I could then use
>>> fping
>>>   fping -g 169.254.0.0/16
>>>   And SHOULD be able to get its address, and then SSH into the box.
>> I was under the impression that zeroconf did some rudimentary name
>> resolution, and you ought to be able to connect to hostname.local
>> (replacing "hostname" with the actual hostname).
>>
>> It'd be a bit dopey if a zero-configuration scheme required you to
>> configure things...
>
> I am doing a little testing, and zeroconf does not seem to be 
> working.  I am seeing the link up light on my ethernet port.  I am 
> seeing a local-scope v6 address, but no v4 address:
>
> p6p1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet6 fe80::ea9a:8fff:fe8d:7b56  prefixlen 64  scopeid 0x20<link>
>         ether e8:9a:8f:8d:7b:56  txqueuelen 1000  (Ethernet)
>         RX packets 7  bytes 2130 (2.0 KiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 46  bytes 4948 (4.8 KiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> Note that it is receiving packets from the other system.   It also has 
> a local-scope ipv6 addr, but no zeroconf addr (both systems are Fedora 
> 20).
>
> So how do I start zeroconf?  Of course on the other system, I can't do 
> that...
>
> So given ipv6 local-scope, how do I learn the other system's addr. 
> Trying to figure out fping6.   How do I restrict it to the desired 
> interface?
>
>>
>>> Any other thoughts?  I can't get to the box to recable it and reboot
>>> it (as that is the only way I can figure out for it to readdress eth0)
>>> until this evening.
>> Only that:  Are you on the same network?  169.254 connections can't be
>> expected to be reachable outside of their own net.
>
> Crossover cable.  Is that enough of a 'same network'?  :)
>
> And I have considerable routing and addressing knowledge.  Besides 
> being one of the authors of rfc 1918, and worked on CIDR, here at IETF 
> I contribute to ipv6ops and ipv6man.
>
>