Interesting.  I deleted entry 8 and then ssh'd to lapdog0 with no complaint.  Logged out, rebooted that machine to Mint and then ssh'd into lapdog1 and that complained about then new entry 23 for lapdog0.

It appears that ssh will make an entry in known_hosts for each IP and something (host name, kernel, tennis ball) combination, but only complains about the 1st mis-match it finds.  Whatever the "something" is is not clear as I got no complaint after deleting entry 8 (from the lapdog2 days) and sshing in to lapdog0.  Puzzling.

On Fri, Nov 30, 2012 at 5:01 PM, Dazed_75 <lthielster@gmail.com> wrote:
I am able to ssh to a machine on the LAN using either host name (my router has dnsmasq turned on) or IP.  That works just fine. 

My confusion started when I took a machine called lapdog2 which used to dual boot Vista and Ubuntu (through several releases) with both named lapdog2.  I would ssh into Ubuntu there with no problem. 

I just replaced the hard drive and only installed ubuntu 12.10 and LinuxMint 14 as a dual boot (yes, it is a bit redundant but I had my reasons) and named them lapdog0 and lapdog1 respectively.  I can still ssh by name or IP but ssh tells me every time that the host key for that IP differs from the one stored when it was lapdog2 (entry 8):  It does not seem to tell me there is any difference for lapdog0 (entry 22) vs lapdog1 (entry 23):

larry@hammerhead:~$ ssh lapdog1
Warning: the ECDSA host key for 'lapdog1' differs from the key for the IP address '192.168.2.124'
Offending key for IP in /home/larry/.ssh/known_hosts:8
Matching host key in /home/larry/.ssh/known_hosts:23
Are you sure you want to continue connecting (yes/no)? yes
Welcome to Linux Mint 14 Nadia (GNU/Linux 3.5.0-17-generic i686)

Welcome to Linux Mint
 * Documentation:  http://www.linuxmint.com
Last login: Fri Nov 30 16:40:24 2012 from hammerhead.thiel.org
larry@lapdog1 ~ $ logout
Connection to lapdog1 closed.
larry@hammerhead:~$ ssh lapdog0
Warning: the ECDSA host key for 'lapdog0' differs from the key for the IP address '192.168.2.124'
Offending key for IP in /home/larry/.ssh/known_hosts:8
Matching host key in /home/larry/.ssh/known_hosts:22
Are you sure you want to continue connecting (yes/no)? yes
Welcome to Ubuntu 12.10 (GNU/Linux 3.5.0-18-generic i686)

 * Documentation:  https://help.ubuntu.com/

14 packages can be updated.
13 updates are security updates.

Last login: Fri Nov 30 16:21:16 2012 from hammerhead.thiel.org
larry@lapdog0:~$

The only thing I can think of is that the name does not matter (it was just resolved by dnsmasq to the same IP) and the old ubuntu was on a different kernel (one of you told me once that the kernel matters for ssh by ECDSA key).

But then why would keys 22 and 23 both be used and without complaint between them?  What am I missing?

--
Dazed_75 a.k.a. Larry

Please protect my address like I protect yours. When sending messages to multiple recipients, use the BCC: (Blind carbon copy). Remove addresses from a forwarded message body before clicking Send.




--
Dazed_75 a.k.a. Larry

Please protect my address like I protect yours. When sending messages to multiple recipients, use the BCC: (Blind carbon copy). Remove addresses from a forwarded message body before clicking Send.