I have a machine that I want to setup an SFTP connection to. The SSH server is running properly, I can ssh into it from my client computer, and I can SFTP in from my smartphone. I'm just a bit confused on how to properly configure the ~/.netrc file. The server computer is running Ubuntu, the client computer is running OSX.
Here are my main requirements for what I'm trying to configure:
Alias. I don't have a DNS name for the computer I'm connecting to, just the IP address. ~/.ssh/config is great because it basically assigns aliases to connections, and then specifies the hostname, port, etc. Looking at the man page for ~/.netrc, I don't see a way to do this.
Private Key. This SFTP connection is validated using a private key. I don't see anything in the ~/.netrc man page about how to specify the key.
If ~/.netrc is the wrong way to go, what alternatives would be better?
Related
I've set up tailscale and connected to an exit node on my VPS on vultr.com. Predictably, I was kicked out and couldn't reconnect, as the VPS's public IP address has changed.
I can reboot the VPS and try again. What steps will I need to take? Does my VPS running behind an exit node even have a unique public address (which?), or does it need to be set up for something like port forwarding?
From looking at tailscale documentation, it looks like they came up with their own ssh, why? Why is the standard ssh inadequate for the purpose? I am not the admin of my tailscale network, and the admin is swamped right now. What can I do?
SSH uses TCP as transport and therefore requires the (srcaddr, srcport, dstaddr, dstport) tuple to be constant over the connection's lifetime.
I believe that since tailscale rotates connections dynamically, it is more suitable for use by clients than servers in a traditional client-server model, unless it provides an 'internal' virtual network over the distributed transport (which would kind of defeat the purpose of covering your tracks).
If you want to connect to your VPS over tailscale, you need to use their tools probably because of that. You can still connect directly to your VPS, though, through plain Internet, if it has any address of its own, and is not firewalled away (or similarly, NATed away). Your provider should either show you the address, or even better, provide access to out-of-band (like serial-port) command line access, where you can query the current addresses using commands like ip addr show.
In your Tailscale Admin console you should be able to see the machine's IP. Just use normal ssh and login that way.
So instead of ssh user#8.8.8.8 you'd do ssh user#100.64.0.1. Tailscale's own ssh client is useful if you want to hook deeper into their MagicDNS stuff, but it's not meant to be the only way to ssh into your machine.
If you run into errors, ping the machine you want to connect to (tailscale ping vps-machine-name). That should help you debug any tailscale client connection problems.
I just created my first VPS host on OVHcloud. When I ssh for the first time I see:
The authenticity of host 'X.X.X.X (X.X.X.X)' can't be established.
ECDSA key fingerprint is SHA256:<the-fingerprint>.
Are you sure you want to continue connecting (yes/no/[fingerprint])?
Is there a way to verify this fingerprint? I know that people most of the time ignore the possibility of a MITM here and skip the check. But most of the time the first connection happens within an internal network, which isn't the case here.
Alternatively I'd be happy to upload an ssh public key to the server using the web manager. But I haven't found a way to do that.
The answer is yes.
I just discovered you can connect to the KVM directly from the OVH manager, thus connecting through tty1.
Go to your OVH manager, and in your VPS page, there should be a part that says "Name". There is then an option in the dropdown menu, "KVM" which let's you locally connect to your VPS through a QEMU instance.
You can get your fingerprints after logging in in this manner.
The answer is no for both questions:
When OVH spawn your VPS, they don't check/gather the auto generated ECDSA key (the ones in /etc/ssh/ssh_hosts_ecdsa*). So for the first connection, there is no way to verify this fingerprint.
For the SSH key upload through the OVH Manager, this is sadly not possible neither. You have to upload it by yourself with ssh-copy-id root#vpsXXX.
Note that it's possible on OVH's Public Cloud Instances, but not for VPS
I'm working on a project that requires me to run my code on a remote Unix server, that is not available to connect to directly (you first have to log in to the "gate" node and then to this server).
What's really bad is that they disabled key authentication, so each time I need to ssh into it, I have to type in my password twice. It's really annoying and I wonder what's the best way to transfer my local modifications of source files to this server, compile and run them without having to provide those passwords so many times.
I have no sudo access to any of those servers (neither to this "gate", nor to this target server). Any ideas on how to make the whole process more efficient?
EDIT: Martin Prikryl provided a great answer below, but it's suitable for Windows and I'm on a Mac :) I guess it might be a good thing to have it documented here also for *NIX systems.
You are looking for SSH tunneling.
WinSCP SFTP client supports one-hop SSH tunneling natively.
See the Tunnel page on WinSCP Advanced Site Settings dialog.
I assume that after you transfer the file, you need to open SSH terminal to compile the file.
You may be able to make use of WinSCP Console window for that step.
Alternatively, if you need/want to use a real SSH terminal client, make use of an existing SSH tunnel, created by WinSCP, and connect with PuTTY (or any other SSH client) over it.
In the Local tunnel port of WinSCP Tunnel page, select a fixed port number (instead of the default Autoselect). In PuTTY enter "localhost" to Host Name and the selected port in Port.
(I'm the author of WinSCP)
I want to make my site available world wide. Im using xampp server for hosting. I have no access to any kind of servers and modems. Situation is shown below:
My site server has local ip assigned by wifi router and it runs Windows 8.
Remember I have no access on any kind of servers and modems so port port-forwarding is impossible (out of my scope).
Its actually difficult, but not impossible.
One way, I would approach this is:
I would host a page on internet.
Then take request and store it in database.
One of my program will always be running from my computer.
Then check for request and curl the request to localhost. For this you may use Node.js (taking data from database using GET method and curl it to localhost).
This is the best I could think of. And I am working on it, when the code is ready I'll make it open source and notify you :)
But still, it's difficult, as you need to put user's request to sleep for 2 seconds and then transferring it.
Its slow, but may work out for you.
Disadvantages:
Program will be very slow and memory usage will be more.
Breaking may happen many times.
High bandwidth wastage
If not encrypted, MIM (Men in Middle) may possible.
Advantages:
Indirect method of hosting
Need not to worry about your code being lost.
I am looking forward for a better alternative and I would like to keep this question for bounty once again.
If you cannot open the necessary ports within your LAN you will require access to an external server. However, the external server does not need to host any code, e.g.
Create a Linux based ec2 instance using Amazon's free tier.
Install a package to redirect remote to local ports:
a. using socat:
Install socat using your distributions package manager
Connect via SSH: ssh -N -R 42500:127.0.0.1:80 -o ServerAliveInterval=60 ubuntu#xxx.xxx.xxx.xxx -N -R 8080:localhost:80 "socat TCP-LISTEN:8080,fork TCP:127.0.0.1:42500"
b. using a webserver and reverse proxy:
Install apache or nginx and any required reverse proxy modules and configure your VirtualHost to proxy requests to a local port, e.g. :8080 -> 127.0.0.1:42500
Connect via SSH: ssh -N -R 42500:127.0.0.1:80 -o ServerAliveInterval=60 ubuntu#xxx.xxx.xxx.xxx
Your machine is now reachable via the ec2 instance http://xxx.xxx.xxx.xxx:8080/.
I occasionally use this technique when debugging web service callbacks.
Update 17-02-2014
If you are a Windows user you will need to install a third-party tool to support ssh. Options include:
cygwin
git bash
PuTTY
PuTTY is the easiest choice if you are not familiar with *nix tools. To configure remote port forwarding in PuTTY expand the following setting: Connection -> SSH -> Tunnels. Given the previously described scenario, populate Source port as 42500, Desination as 127.0.0.1:80 and tick the Remote option. (You may also need to add the path to a PuTTY compatible private key in the Connection -> SSH -> Auth tab depending on your server configuration.
To test you have successfully forwarded a port, execute the command netstat -lnt on your server. You will see output similar to:
tcp 0 0 127.0.0.1:42500 0.0.0.0:* LISTEN
Finally you can test with curl http://127.0.0.1:42500. You will see the output of your own machines web root running on port 80.
if you don't have a public IP address and cannot use port forwarding it is impossible to host the site
As people have said you need a public IP address. However, even if you did you should not use xampp as a public server, as it is designed for development and therefore has some security settings disabled.
I would recommend buying some shared web hosting, and uploading it to that. (you can get cheap hosting if you google 'shared web hosting', plus free .tk domains are avaliable: http://www.dot.tk/)
Do your company has any vpn network?
If it does and you have access to the vpn network, you can include your server to the vpn network and your guest will only need to login to your company vpn network then access your site like in a local network without using port forwarding. And since your data is very confidential, I assume that using vpn will also help to increase the security of your data.
Please correct me if I'm wrong.
Thank You.
What you are asking is not possible without port forwarding.
Lets break it into steps.
To host your site locally you will need a IP that is static so that
users can access it specifically.
You will need a domain so that it can be converted into user friendly name.
A 24x7 Internet Connection is must! You added a Wifi Router in your Diagram and most of today's router are capable of port forwarding.
What i will do in your scenario is:
Instead of using XAMP, i will install WAMP because i am more familiar with it and easy to configure.(totally personal preference)
Then i would set my server "ONLINE".(Google how to set WAMP server online)
Forward port "80" from router settings to my local computer ip address.(mostly it is tagged as "Virtual Server","Firewall","Port Forwarding",etc vary router to router in settings)
Suppose you have a local ip "192.168.1.3" and global/router IP "254.232.123.232" then you would redirect all the HTTP request done towards router to your local IP.
[[[[254.232.123.232]]]] --+ :80 +-- --------->192.168.1.3
That is good for now, but then you will need to tackle dynamic IP problem of router. But don't worry, thanks to some free sites that will be easy!
Go to no-ip.org -> Setup Account -> and create a entry, just a subdomain for now to test whether everything is working fine.(subdomain like mysite.no-ip.org, later purchase a real Domain)
Input your IP address there(Router IP) and download its application which will automatically update their server if your local IP changes.
Wait for some minutes and Voila! Your site is live.
I'd like to use a server between two machines (with no static IP). The only IP known to me is the server's IP address. I'd like to build/use a system that listens to 2 different ports within the server and whatever is received from localhost:portA is sent to localhost:portB and vise versa. Consequently, both machines (with java apps) can communicate through the server in the middle.
Please what is the best solution to do this. I'm working on linux system and I thought of using an SSH java API (hudson / ganymed-ssh-2) to build a port forwarding server application.
Some issue:
1) determining the size of the data transmitted to buffer read or not to forward it to the other port.
2)The speed of reading/writing bytes.
If you can use ssh protocol you can tunnel local or remote ports (this need support on server side). You can also think about an OpenSSH VPN (take a look on ssh -w option, this will create a real VPN (TUN/TAP device is required). ).
You can use the the ssh program. Take a look at the -L and -R options specifically.