I can't connect via ssh

[Erik Hemdal]

.
> Message: 2
> Date: Sat, 26 Sep 2009 17:23:17 -0300
> From: Germ?n Racca <german.racca at gmail.com>
> Subject: Re: I can't connect via ssh
> To: "Community assistance, encouragement, and advice for using
> Fedora." <fedora-list at redhat.com>
> Message-ID: <1253996597.1845.16.camel at centauri.das.inpe.br>
> Content-Type: text/plain; charset="UTF-8"
>
> On Sat, 2009-09-26 at 15:30 -0400, Erik Hemdal wrote:
>>
>> > From: Germ?n Racca <german.racca at gmail.com>
>> > Subject: Re: I can't connect via ssh
>> > To: "Community assistance, encouragement, and advice for using
>> > Fedora." <fedora-list at redhat.com>
>> > Message-ID: <1253925734.7784.27.camel at centauri.das.inpe.br>
>> > Content-Type: text/plain; charset="UTF-8"

> Hi Erik,
>
> Thanks for your clarifying message! Now I discovered the following:
>
> I can ping and connect via ssh from other computer to my notebook, but
> *I can't from other computer to my PC*. The messages, from other
> computer to my PC are:
>
> $ ssh xx.xx.xx.xx
> ssh: connect to host xx.xx.xx.xx port 22: No route to host
>

OK, so what can we learn from this?

Your notebook has a working configuration of the SSH server and it can be 
found on the network.
Your "other computer" probably has a good configuration of the SSH client.

If you end up with SSH troubles, knowing which systems have known-good 
setups can be very important.  But from what you've told me, I don't yet 
suspect SSH is the problem, there's something else.  You aren't even 
reaching SSH on the computer you want to get to.

> $ ping xx.xx.xx.xx
>>From xx.xx.xx.xx icmp_seq=11 Destination Host Unreachable

So if I understand things, there are three computers here:  The "PC", which 
is the computer you're trying to access, let's call that "Alpha", another 
computer, let's call it "Baker", and your notebook, let's call it "Charlie".

Baker can "ssh into" Charlie.  But neither Baker nor Charlie can ssh into 
Alpha.  And Alpha is the one you really need to reach.  Further,you can't 
even ping Alpha, you get the "no route to host" errors.  Since you get them 
from two different computers, Baker and Charlie, I'm more suspicious that 
something on Alpha is the problem, or something on the network (the common 
link) is wrong.

If I were there, I would check  a few things.  I'd log on to Alpha and see 
what I can do FROM that computer.  Can you browse the Web, ping other 
computers, and so forth?   That might tell us a lot.  For example, if the 
network cable on that computer is loose or broken, you'd see these problems.

Then, I'd try to look at the equipment itself:  What is the computer 
connected to on the network?  For example, it might go into a network box 
right there in the room, or it might just go into the wall.  If the first 
case is true, then you can check the network connections that are there.  If 
the network cable goes into the wall, you probably need to talk to the 
network admins for help. When other posters were asking about your physical 
setup, this is what they were asking about.

If you can reboot Alpha, or at least restart its network service, you might 
cure the problem too.  But you need to know if Alpha is working right first; 
don't just turn it off if you don't have to.

Erik

>
> I'm going to contact the network administrator on Monday, but I hope
> that you and the other guys that answered to my post can continue to
> help me on this issue. Sorry for my bad English ;-)
>
> Germán.
> -- 
> Germán A. Racca
> National Institute for Space Research (INPE)
> São José dos Campos - SP - Brasil
> http://gracca.wordpress.com
> http://tinyurl.com/SkyTux
>
> .