Re: Fwd: SSHD not connecting from outside(real) IP

[Lee <ler762 at gmail dot com>]

On 1/4/16, Adam Dinwoodie wrote:
> On Mon, Jan 04, 2016 at 06:05:32PM -0200, JoÃo Paulo wrote:
>> Hello all,
>> I have a mystery and I need help. I have openssh(Cygwin) installed
>> and working just fine in here.
>> I can connect normally from any of my machines to the server using
>> local IPs. Ex: ssh localhost or ssh 192.168.0.2. BUT, when using my
>> external IP(over internet->real IP) it times out.
>> I can validate that the service is up and running on
>> http://www.canyouseeme.org/ on the port FW I did for this service.
>> Port 22 is correctly FW to my SSHD server. On windows, I can only
>> see an entry on Security Events(attached) and nothing else after
>> that. (Means it is reaching my machine)
>> I have tried to reinstall Cygwin, change ports. sshd_config is in
>> default, disable firewall, AV. I ran out of ideas......
>> I had this working fine on previous window 7, now I am on Windows 10.
>> Thanks.
>
> To check I'm understanding you correctly: you're using Cygwin on your
> Windows 10 machine to run an sshd service, you're attempting to connect
> to this using SSH from another machine, this works when the other
> machine is within your local network but not when the other machine is
> external.
>
> If that's the case, I think it's very unlikely that Cygwin is the
> problem  -- if Cygwin were the problem, I would expect connections to
> fail on your local network too.  To check that, can you run a packet
> capture on the system running Cygwin sshd while you attempt to connect?
> I expect it will show no received packets, which means the problem lies
> elsewhere in your network.
>
> For packet capture I normally use Wireshark, but alternatives are
> available (doing it on your router would be ideal if it supports that).

Just be aware that a wireshark capture on the target machine captures
packets _before_ they're processed by the windows firewall, so if
wireshark shows the packets reaching the machine make sure to also
check the windows firewall log.

Regards,
Lee

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