ssh: Could not resolve hostname [hostname]: nodename nor servname provided, or not known

If you're on Mac, restarting the DNS responder fixed the issue for me.

sudo killall -HUP mDNSResponder

I had the same issue connecting to a remote machine. but I managed to login as below:

ssh -p 22 myName@hostname

or:

ssh -l myName -p 22 hostname

Recently I came across the same issue. I was able to ssh to my pi on my network, but not from outside my home network.

I had already:

• installed and tested ssh on my home network.
• Set a static IP for my pi.
• Set up a Dynamic DNS service and installed the software on my pi. I referenced these instructions for setting up the static ip, and there are many more instructional resources out there.

Also, I set up port forward on my router for hosting a web site and I had even port forward port 22 to my pi's static IP for ssh, but I left the field blank where you specify the application you are performing the port forwarding for on the router. Anyway, I added 'ssh' into this field and, VOILA! A working ssh connection from anywhere to my pi.

I'll write out my router's port forwarding settings.

(ApplicationTextField)_ssh     (external port)_22     (Internal Port)_22     (Protocal)_Both     (To IP Address)_192.168.1.###     (Enabled)_checkBox

Port forwarding settings can be different for different routers though, so look up directions for your router.

Now, when I am outside of my home network I connect to my pi by typing:

ssh pi@[hostname]

Then I am able to input my password and connect.