[CentOS] Multiple FreeNX servers and SSH ports

Niki Kovacs contact at kikinovak.net
Sun Mar 21 17:03:12 UTC 2010


Ned Slider a écrit :

> Choose a random unused high port number (above 1023)
> 
> http://www.iana.org/assignments/port-numbers.
> 
>> 2) How do I configure these different ports ? By that, I mean : how do I 
>> tell SSH to use them instead of port 22 ?
>>
> 
> http://wiki.centos.org/HowTos/Network/SecuringSSH#head-3579222198adaf43a3ecbdc438ebce74da40d8ec

Thanks, that helped. I sort of managed to configure different SSH ports 
for the two machines. Now I'm facing another quite unexpected problem. 
Let me try to describe what's going on.

Machine number 1 (bernadette) is 192.168.1.2. I reconfigured SSH on this 
machine to use port 10022.

Machine number 2 (raymonde) is 192.168.1.3. SSH port on raymonde is 10023.

I took care of reconfiguring the firewall and open the respective ports 
(10022:tcp on bernadette, 10023:tcp on raymonde).

In my router's web interface (Expert Mode > NAT) I defined a port 
redirection, so that requests for port 10022 are rerouted to 
192.168.1.2, and requests for port 10023 to 192.168.1.3.

Now I can ssh into my two machines from the outside, using my public IP 
address. E. g. :

# ssh my.ip.add.res -p 10022 --> I'm logged into bernadette

# ssh my.ip.add.res -p 10023 --> Logs me into raymonde

Except... when logging in a second time, in the other machine, I get 
this, understandably :

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.


Now, of course, I could manually open ~/.ssh/known_hosts, erase the 
respective line and then log back again. But is there a more orthodox 
way to log into two different machines via two distinct ports on one 
single IP address without getting this sort of error ?

Cheers,

Niki


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