I have a computer at my college that I always ssh into from my laptop. However, I'm leaving for break soon, and I realize that whenever I try to ssh in from a different network, the server won't let me in. I really would like to be able to ssh into this computer during break, so what should I do?
Whenever I type this into terminal:
XXXXXXXXXX$ ssh -X XXXXXXX#XXXXX.XXXXX.XXXX.XXX.XXX
The process either won't go forward, or I get this error message:
ssh: Could not resolve hostname XXXXX.XXXXX.XXXX.XXX.XXX: nodename nor servname provided, or not known
Yes, you can, thru ssh-tunnelling. See this link.
The problem is that, you need to have a box of public fixed IP address outside of your school.
If you have a public floating address, it's still possible. First, you will need DDNS (just search 'DDNS' on the web), or other method for your server to get your client's IP address. For example, in your personal web page, somewhere, stores your current client's IP floating IP address. Then, you need a script/program to fetch that address. After that, apply the same ssh-tunneling technique. (Yet, you need a script/program to automatically apply all these steps, yet fail safe issue: When your client's is disconnected, your ssh-tunnel will break, and your ssh-tunneling process died. Your script need to sense it and re-launch (after getting the new floating IP address).
Oh, the pre-assumption is that, you need to be able to ssh from your school server (your linux box in school) to an outside server (a linux box in your home, for example). I think most school won't block ssh access to servers outside of the school.
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Thanks in advance.
I have setup a server in which I intend to host a couple of applications but something weird is happening, I have bought a couple of domains which I have all mapped to the same ip address, but now when trying to ssh to that server only one of the domains goes through, the rest don't.
Someone please explain why this is happening and what I could have probably done wrong
Am I correct that you are attempting to connect to the different domains via different saved configurations in your SSH terminal app. If so, check that you have connected each of those configurations to the appropriate private key. And of course check any other settings you may have needed in those configurations.
For example, make sure that if the host name for the working one is <username>#<domainOne> then the others are not simply <domainTwo.com>. (Errors like this can be hidden in some SSH terminals if the domain is very long.)
I have a client who is remote. I need to debug some weird problem that none of my other clients are having. Before I try and set up a conference with this client, I would like to know if there is some way of remotely debugging our application.
I see that there are remote debugging tools available for Visual Studio, but from what I've read, I need to be on the same subnet. As the person is remote, this is not a possibility. Also, as I'd like to keep our connection secure, I would need to connect up some sort of encrypted tunnel (this is where I'm a little fuzzy as my networking skills are mostly theoretical).
As I understand it, an encrypted tunnel is a bridge to another (different) subnet. This is to ensure that those computers on the other side won't interfere with the local subnet computers.
So, because the client's computer is on a different subnet, I think that this is not possible. Or is it? Should there not be a way of making the client's computer show up as a virtual computer on my subnet, by forwarding packets from one subnet to another? I would think that this is theoretically possible, but I'm not exactly sure how I would go about this.
Also, at the moment, my current way that we connect to clients is through GoToMeeting, but I don't think that it supports tunneling. If not, then I may need some way of generating a tunnel, so I was also thinking of maybe using some SSH programme like PuTTY.
As I have said before, my knowledge of networking is quite theoretical, so if the tools that I am suggesting are not the correct ones, please correct me. (I'm a programmer, damm it! Not a network engineer!)
Both computers are Windows boxes. Windows 10 (client) and Windows 8.1 (development).
If you can connect to an ssh server in the remote network, you can (subject to configuration on the server) create a tunnel such that you connect to a socket on your local pic and the connection appears from the server to an endpoint on the remote network.
You'll want to investigate the -L command of OpenSSH, which combined with the PuTTY docs, should help explain what's required.
By default, the endpoint would be a port on the ssh server, but it could be a port on a different host that the remote server can connect to.
I'm not familiar with the current state of Windows SSH servers, but even if there isn't a system server to hand, you should be able to have on run 'on demand' - if you run it on a non-privileged port and by the user you want to connect in as, it shouldn't even need Admin privileges.
I'm not familiar with GoToMeeting, but the one thing with SSH tunnelling it that IT depts should be familiar with SSH. If trying that, focus on getting a working connection in, then setting up the tunnel, then connecting through it as separate steps.
Once you have an SSH connection, then it doesn't need to do something itself, and you can then investigate connecting while specifying the port forwarding, but will will need to get the basic connection working correctly first.
This is probably incredibly simple and I'm just missing one step. The problem I was (originally) trying to solve was how to get a statically allocated hostname, one that would not change with each restart. I've done the following steps:
I have a domain registered on GoDaddy, and it points to my EIP. I use it to connect over SSH (putty) to my EC2 instance, so I know that part is working. I've opened ports 9080, 9060, 9043, and 9443 as well as SSH and FTP ports. And I've installed and started the software that uses those ports, and that stuff normally just works on a local RHEL install, so I think what's different here is the custom domain name.
I've added my EIP and fully qualified host name to my /etc/hosts file.
I've added my fully qualified host name to my /etc/hostname file and modified the /etc/rc.local script to set the hostname properly on a restart, and that works. If I execute the command hostname, it returns my fully qualified hostname, so that looks ok.
I cannot ping my server, but I think that's ok, because probably amazon blocks pings. So I don't think that's a symptom of anything.
I cannot open a to http://myserver.mydomain:9080/, which normally just works. Here it just times out.
If I do a wget http://myserver.mydomain:9080 from inside the EC2 instance, it returns failed: No Route To Host
But if I do a wget against localhost instead of the fully qualified name I get what I expect as a response.
So.... routing tables? Do those need to change? And if so how?
You probably don't want to do what you did. Everything in EC2 is NAT'd. Meaning that the IP assigned to your instance is a private/internal ip and the public IP is mapped to it by the routing system.
So internally, you want everything to resolve to the private IP, or you will get charged for traffic as it has to get routed to the edge and then route back in. Using the public DNS name will resolve correctly from the default DNS servers.
If you are using RHEL, you will need to make sure both the security group and the internal firewall (iptables) have ports opened. You could just disable the internal firewall since its a bit redundant with the security groups. On the other hand, it can provide some options security groups do not if you need them.
i have created new instance in amazon ec2, and assigned the elastic ip for instance. But i need to know how to get ip for name server (ns1.abc.com, ns2,abc.com).
I have installed whm in amazon instance. Only domain cannot point to the correct name server. That is because ip cannot load.
Now, my problem is that how i get new ip. Can i add another two elastic ip in amazon? But i configured two elastic ip for name server in dns zone within whm. The name server is not working. And i cannot open the elastic ip in browser. I am confuse for it. Please anyone help me.
There are lots of things that can go wrong here. I'll try to troubleshoot step by-step:
I'll assume the goal is "You want to type 'whm.foo.com' and see your WHM"
1) Go to your domain registrar and make an entry that points "whm.foo.com" to your EIP. (Depending on what you want, maybe you should setup a "*.foo.com" wildcard for that EIP.
2) Test that step #1 worked by typing "ping whm.foo.com" or "dig whm.foo.com" (one linux/mac, not sure about Windows). This should return your EIP. If not, go back to step 1.
3) Check that WMH is acually running. Read the docs to find what port it's running on. (Usually 2083, or 2082 for insecure access)
On your instance, run "curl -v localhost:2083" (or whatever port. It should return a login screen. If it says "couldn't connect to host", then you have the wrong port or it's not running.
4) run "netstat -na | grep :2083" (or whatever port). It should say "0.0.0.0:*". If it says "127.0.0.1:*", then you need to configure it to allow outside access.
5) Make sure your WHM port is enabled in the AWS firewall. Go to the AWS control panel and find the security group for your box. Make sure that port is allowed. Ideally, you'd only add your personal IP instead of opening it up to the world. (If there is a bug in WHM, people will scan all IPs trying to exploit it. They can't exploit your server if the AWS firewall denies them access.)
6) Now type "https://whm.foo.com:2083" (or whatever port) in your browser. (or http://whm.foo.com:2082 for insecure access). It should work!
i need to know how to get ip for name server (ns1.abc.com, ns2,abc.com).
As rdrey said, you need to go to your DNS provider (most registrars also do DNS) and tell them what boxes should point to your EIP.
That is because ip cannot load.
There is no such thing as "ip cannot load". Either "DNS is giving the wrong IP" or "some IP operations (TCP ports) were blocked by a firewall somewhere".
Now, my problem is that how i get new ip
I don't think that should be your goal. You can easily change EIPs, but it won't fix the problem. Nothing works unless everything in between is set up correctly. The goal should be understanding all the steps in the process and verifying that each step was done correctly.
OK, you have two options here:
Use the DNS servers provided by your Domain Registrar OR
Use AWS Route53 to let Amazon provide DNS services for you.
Option 1:
You bought your domain name from a registrar, like one of these: http://lifehacker.com/5683682/five-best-domain-name-registrars
Most, if not all, registrars run a free DNS service for their customers. You should be able to log into some kind of management console and set your domain's DNS zone entries to point at your AWS EIP. (I am using gandi.net and used to use godaddy. You simply leave the DNS Servers as they are and set your AWS EIP as the 'A' record.)
Option 2:
Go to https://console.aws.amazon.com/route53/home and follow instructions. I haven't read up on Route53's pricing, so this option might not be free.
---- EDIT:
Some more help:
The site you've linked to (http://www.intodns.com/xantec.com.sg) states that you've used your EIP (54.251.169.7) as the nameserver for the domain. You don't want that. You're running a cPanel installation, NOT a DNS nameserver.
Put 54.251.169.7 as your site's A record. (Sometimes called the www field.) Remove it from the NS fields and put ns3.thesimpledns.com & ns4.thesimpledns.com into those.
I just set up eduroam on my laptop and this morning when I fired up my terminal, I noticed that my hostname has been changed most probably by the eduroam set up to a new value. Any ideas why or how this happens?
You're going to get a new hostname every time you join a new network (at least potentially). The hostname identifies the computer and is therefore assigned by the network that you connect to. This usually happens as part of DHCP, where you get an IP address and routing information.
This is perfectly normal and nothing to worry about. If you absolutely need a certain hostname, talk to the network administrators.