ssh: Could not resolve hostname [hostname]: nodena

问题:

I am trying to set up a VPN with a Raspberry Pi, and the first step is gaining the ability to ssh into the device from outside my local network. For whatever reason, this is proving to be impossible and I haven't the slightest clue why. When I try to ssh into my server with user@hostname, I get the error:

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

However, I can log into the server with,

ssh user@[local IP]

The server is a Raspberry Pi Model B running the latest distribution of Raspbian and the machine I am trying to connect to it with is a Macbook Pro running Mavericks. ssh was enabled on the Raspberry Pi when I set up Raspbian.

I have perused Stack Overflow for hours trying to see if anyone else had this problem and I have not found anything. Every ssh tutorial I find says that I should just be able to set it up on the remote machine and log in from anywhere using a hostname, and I have never had success with that.

回答1:

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.

回答2:

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

回答3:

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

sudo killall -HUP mDNSResponder

回答4:

If you need access to your VPN from anywhere in the world you need to register a domain name and have it point to the public ip address of your VPN/network gateway. You could also use a Dynamic DNS service to connect a hostname to your public ip.

If you only need to ssh from your Mac to your Raspberry inside your local network, do this: On your Mac, edit /etc/hosts. Assuming the Raspberry has hostname "berry" and ip "172.16.0.100", add one line:

# ip           hostname
172.16.0.100   berry

Now: ssh user@berry should work.

回答5:

I had the same issue, which I was able to resolve by adding a .local to the host name, ala ssh [e-mail]

回答6:

I had the same problem: The address shown in Preferences -> Sharing -> Remote Login didn't work and I got a '... nodename nor servname provided, or not known'. However, when I manually edited the settings (in Preferences -> Sharing -> Remote Login -> edit) and enabled "Use dynamic global hostname", it suddenly worked.

回答7:

If your command is:

$ ssh -p 1122  path/to/pemfile user@[hostip/hostname]

You will also face the same error

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

when you miss the option -i /path/to/pemfile of ssh

So Command should be:

$ ssh -p 1122 -i path/to/pemfile user@[hostip/hostname]

回答8:

This was happening to me when trying to access Github. The problem is that I was in the habit of doing:

git remote add <xyz> ssh:\\[e-mail]......

But, if you are having this error from the question, removing ssh:\\ may resolve the issue. It solved it for me!

Note that you will have to do a git remote remove <xyz> and re-add the remote url without ssh:\\.

回答9:

I needed to connect to remote Amazon server

ssh -i ~/.ssh/test.pem -fN -L 5555:localhost:5678 [e-mail]

I was getting the following error.

ssh: Could not resolve hostname <hostname.com>: nodename nor servname provided, or not known

Solution For Mac OSX

Pinging the host resolved the issue. I am using Mac OSX Seirra.

ping hostname.com

Now problem resolved. Able to connect to the server.

Note: I tried this solution also. But it didn't work out. Then ping resolved the issue.

回答10:

It seems that some apps won't read symlinked /etc/hosts (on macOS at least), you need to hardlink it.

ln /path/to/hosts_file /etc/hosts

回答11:

Try this, considering your allowed ports. Store your .pem file in your Documents folder for instance.

To gain access to it now all you have to do is cd [directory], which moves you to the directory of the allotted file. You can first type ls, to list the directory contents you are currently in:

ls
cd /Documents
chmod 400 mycertificate.pem
ssh -i "mycertificate.pem" [e-mail] -p 80