Unable to ssh nodes with global IP

[Marko Vojinovic]

On Monday 24 October 2011 12:15:03 Abu Attar Musharih wrote:
> I tried INCOMING ssh several times  and check file /var/log/secure
> No entries related to login attempt found.
> Now, it becomes even worse. Yesterday I could do OUTGOING ssh, but not
> anymore. The following site is inaccessible
> 
> http://www.yougetsignal.com/tools/open-ports/
> 
> While using different provider, there is no problem.

I think that by now it is obvious that the problem is not with your machine, 
and that your ISP has closed down the ports. Your choices are probably the 
following:

(1) Talk to your provider and ask them to open all ports to your IP. This is a 
reasonable request, since you have a public IP number, and should be able to 
use it however you like (provided that nobody complains about spam or attacks 
coming from your IP). Note, though, that the ISP may choose to charge you 
extra money for this.

(2) Change the ISP for another that is more forthcoming.

(3) Scan your IP from outside for any open ports, pick one and use it for 
ssh/openvpn/whatever, without discussing it with your ISP. This will work, but 
may not be considered legal by the ISP. Also, you might have a hard time 
choosing a port, if only a few of them are open, since you may need them all 
for their regular job (like ports 80/443 for the web, 25 for e-mail, etc.).

YMMV.

Best, :-)
Marko