Ubuntu – Cannot Connect to the AWS Lightsail Instance

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My Amazon Lightsail instance was working fine until 1 hour before. I opened some ports in the network config in the browser dashboard and since then I cannot connect to the server. All the hosted websites are down and simply the instance is not working. I rebooted the server, but no luck. I am in a terrible situation right now. I don't know whether the instance has crashed altogether. Seems there's nothing that I could do at this point. Is this common? There's no way to contact the amazon support on this.

Update: After Tim's comment the firewall setting:

This didn't work until 465, 587 and 9000 were removed. After that, everything was ok. The 3 ports mentioned above being the only three ports that were open earlier, ssh port, 22, was missing from the list. Therefore, I wasn't able to establish a connection.

Best Answer

General this kind of problem is caused by a firewall. In full AWS this tends to be security groups or NACLs, but LightSail appears to be a simpler firewall interface.

Try to close any ports you don't need open. For example, if you don't use SSH, close port 22.

Related Solutions

Amazon EC2 – How to SSH into Instance Without .pem File

In short: Yes, you can, but not without some work.

You'll need to do the following:

(For these steps, assume that the machine you're having trouble connecting to is called server-01.)

First, before starting these steps, take a snapshot of your server.

Start a new, temporary instance. Call it server-02.
Stop server-01. Don't terminate it, just stop it.
Un-attach the root (/) EBS volume from server-01, and attach it to server-02 as, say /dev/sdb.
Sign into server-02, and run: $ mkdir /mnt/temp && mount /dev/sdb /mnt/temp. This will mount server-01's root partition within the (temporary) server-02.
Now you should be able to: $ vi /home/<user>/.ssh/authorized_keys and copy/paste in your public key. When you've done that, save and close the file.
Now run: $ cd / && umount /mnt/temp to umount server-01's root partition from server-02.
Now, just un-attach that volume from server-02, attach it back to server-01, and then start server-01. When it starts up, you should be able to ssh in again.

Can’t connect to AWS instance after import with stock Centos7

did you configure the eth0 before importing the machine (/etc/sysconfig/network-scripts/ifcfg-eth0 if I recall well on Centos)? it should look something similar to:

DEVICE=eth0 
BOOTPROTO=dhcp
ONBOOT=yes
TYPE=Ethernet
USERCTL=yes
PEERDNS=yes
IPV6INIT=no
PERSISTENT_DHCLIENT=yes

(check especially IPV6INIT setting)

Also make sure iptables service is off at boot time(run "sudo chkconfig iptables off" before importing the machine), and security group is opened for your ec2 instance

Best Answer

Related Solutions

Amazon EC2 – How to SSH into Instance Without .pem File

Can’t connect to AWS instance after import with stock Centos7

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